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All questions of Structure of the Atom for Class 9 Exam
Na+ has 12 neutrons and 10 electrons. Which of the following statement is correct?- a)Na+ has atomic number equal to 10 and mass number 22
- b)Na+ has atomic number equal to 11 and mass number 23
- c)Na+ has atomic number equal to 10 and mass number 23
- d)Na+ has atomic number equal to 11 and mass number 22
Correct answer is option 'B'. Can you explain this answer?
Na+ has 12 neutrons and 10 electrons. Which of the following statement is correct?
a)
Na+ has atomic number equal to 10 and mass number 22
b)
Na+ has atomic number equal to 11 and mass number 23
c)
Na+ has atomic number equal to 10 and mass number 23
d)
Na+ has atomic number equal to 11 and mass number 22
 | Geetika Shah answered |
The chemical symbol Na+ represents a sodium ion. The atomic number of sodium (Na) is 11, which means it has 11 protons.
Given that Na+ has 12 neutrons, we can determine the mass number by adding the number of neutrons to the number of protons. So, for Na+:
Given that Na+ has 12 neutrons, we can determine the mass number by adding the number of neutrons to the number of protons. So, for Na+:
Mass number = Number of neutrons + Number of protons Mass number = 12 neutrons + 11 protons Mass number = 23
The atomic number remains unchanged because it is determined by the number of protons, which is characteristic of each element. The loss or gain of electrons to form ions does not change the atomic number.
Therefore, the correct statement is: Na+ has an atomic number equal to 11 and a mass number of 23.
In an atom, the mass number of an atom is equal to the number of___________.- a)nucleons
- b)protons
- c)electrons
- d)neutrons
Correct answer is option 'A'. Can you explain this answer?
In an atom, the mass number of an atom is equal to the number of___________.
a)
nucleons
b)
protons
c)
electrons
d)
neutrons
 | Anisha Yadav answered |
Mass Number of an Atom:
The mass number of an atom is the sum of the number of protons and neutrons in the nucleus of an atom. It is denoted by the symbol A.
Formula for Mass Number:
Mass Number (A) = Number of Protons (Z) + Number of Neutrons (N)
Explanation of the Answer:
In an atom, the mass number is equal to the total number of nucleons. Nucleons are the particles found in the nucleus of an atom. They include protons and neutrons. Electrons are not included in the mass number calculation because they are much lighter than protons and neutrons and their mass is negligible in comparison.
Therefore, the correct answer is option 'A' which states that the mass number of an atom is equal to the number of nucleons.
Conclusion:
The mass number of an atom is a crucial concept in nuclear physics and chemistry. It helps in determining the stability and properties of an atom. The atomic mass of an element is the weighted average of the mass numbers of all the isotopes of that element.
The mass number of an atom is the sum of the number of protons and neutrons in the nucleus of an atom. It is denoted by the symbol A.
Formula for Mass Number:
Mass Number (A) = Number of Protons (Z) + Number of Neutrons (N)
Explanation of the Answer:
In an atom, the mass number is equal to the total number of nucleons. Nucleons are the particles found in the nucleus of an atom. They include protons and neutrons. Electrons are not included in the mass number calculation because they are much lighter than protons and neutrons and their mass is negligible in comparison.
Therefore, the correct answer is option 'A' which states that the mass number of an atom is equal to the number of nucleons.
Conclusion:
The mass number of an atom is a crucial concept in nuclear physics and chemistry. It helps in determining the stability and properties of an atom. The atomic mass of an element is the weighted average of the mass numbers of all the isotopes of that element.
The number of valence electron in Na is –- a)1
- b)2
- c)3
- d)4
Correct answer is option 'A'. Can you explain this answer?
The number of valence electron in Na is –
a)
1
b)
2
c)
3
d)
4
 | Reema Singh answered |
1. Na has one valence electron.
An atom with 3 protons and 4 neutrons will have a valency of - a)3
- b)7
- c)1
- d)4
Correct answer is option 'C'. Can you explain this answer?
An atom with 3 protons and 4 neutrons will have a valency of
a)
3
b)
7
c)
1
d)
4
 | Shreeya Joshi Joshi answered |
Yeah as no.of protons= electrons
Number of electrons will be 3 so configuration will be 2,1 so therefore that element will need to give 1 electron to satisfy duplet rule.
If I am not wrong is the element Beryllium???
Wonderful question!
Number of electrons will be 3 so configuration will be 2,1 so therefore that element will need to give 1 electron to satisfy duplet rule.
If I am not wrong is the element Beryllium???
Wonderful question!
What is the no. of electrons in Argon?- a)16
- b)17
- c)18
- d)19
Correct answer is option 'C'. Can you explain this answer?
What is the no. of electrons in Argon?
a)
16
b)
17
c)
18
d)
19
 | Shweta Pandey answered |
Argon has 18electrons
A=Z+N
A=mass number
Z=number of protons in nucleus
N=number of neutron in nucleus
Z=e=p (number of electron )
sol~
A=39
Z=e=p=18
N =21
second method is, (Aufbau Principle)
Ar=18
1s2,2s2 2p6,3s2 3p6.
A=Z+N
A=mass number
Z=number of protons in nucleus
N=number of neutron in nucleus
Z=e=p (number of electron )
sol~
A=39
Z=e=p=18
N =21
second method is, (Aufbau Principle)
Ar=18
1s2,2s2 2p6,3s2 3p6.
The no. of electrons in the valence shells of Sodium and Calcium repectively:- a)1, 1
- b)2, 1
- c)1, 2
- d)2, 2
Correct answer is option 'C'. Can you explain this answer?
The no. of electrons in the valence shells of Sodium and Calcium repectively:
a)
1, 1
b)
2, 1
c)
1, 2
d)
2, 2
 | Partho Saini answered |
Electronic configuration of
Na is 2, 8, 1
Ca is 2, 8, 8, 2
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : The size of the nucleus is very small as compared to the size of the atom.Reason : The electrons revolve around the nucleus of the atom.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Assertion (A) is false but reason (R) is true.
Correct answer is option 'B'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : The size of the nucleus is very small as compared to the size of the atom.
Reason : The electrons revolve around the nucleus of the atom.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Assertion (A) is false but reason (R) is true.
 | Avinash Patel answered |
The nucleus of an atom is about 10-15 m in size; this means it is about 10-5 (or 1/100,000) of the size of the whole atom. A good comparison of the nucleus to the atom is like a pea in the middle of a racetrack. (10-15 m is typical for the smaller nuclei; larger ones go up to about 10 times that.)
Atomic number of any element–- a)Atomic weight divided by two
- b)Nucleus weight
- c)Electrical charge of nucleus
- d)Total charge of electrons
Correct answer is option 'C'. Can you explain this answer?
Atomic number of any element–
a)
Atomic weight divided by two
b)
Nucleus weight
c)
Electrical charge of nucleus
d)
Total charge of electrons
 | Let's Tute answered |
- The atomic number of an element is the number of protons in its nucleus.
- This defines the identity of the element and determines its position in the periodic table.
- Since protons have a positive charge, the atomic number is effectively the electrical charge of the nucleus.
- Electrons, which are negatively charged, balance this charge in a neutral atom.
- Therefore, the atomic number is best described as the electrical charge of the nucleus, making option C correct.
- This defines the identity of the element and determines its position in the periodic table.
- Since protons have a positive charge, the atomic number is effectively the electrical charge of the nucleus.
- Electrons, which are negatively charged, balance this charge in a neutral atom.
- Therefore, the atomic number is best described as the electrical charge of the nucleus, making option C correct.
The atomic number of an element is equal to:- a)The number of electrons in the nucleus
- b)The number of neutrons in the atom
- c)The number of protons in the nucleus
- d)The total number of nucleons
Correct answer is option 'C'. Can you explain this answer?
The atomic number of an element is equal to:
a)
The number of electrons in the nucleus
b)
The number of neutrons in the atom
c)
The number of protons in the nucleus
d)
The total number of nucleons
 | Rishabh Unni answered |
Understanding Atomic Number
The atomic number is a fundamental property of an element that defines its identity in the periodic table.
Definition of Atomic Number
- The atomic number is defined as the number of protons in the nucleus of an atom.
- It is denoted by the symbol 'Z'.
Significance of Protons
- Protons are positively charged particles found in the nucleus.
- The number of protons determines the element's chemical properties and its place in the periodic table.
Relation to Electrons
- In a neutral atom, the number of electrons equals the number of protons.
- This balance of charges ensures the atom is electrically neutral.
Neutrons and Nucleons
- Neutrons are neutral particles in the nucleus and do not affect the atomic number.
- The total number of protons and neutrons in an atom is known as the mass number, which is different from the atomic number.
Why Option 'C' is Correct
- Option 'C', stating that the atomic number equals the number of protons in the nucleus, is accurate.
- This definition directly correlates with the identity of the element.
Summary
- The atomic number is fundamental for identifying elements.
- It directly influences an element's chemical behavior and its placement in the periodic table.
- Understanding the atomic number helps in grasping concepts in chemistry and atomic structure.
The atomic number is a fundamental property of an element that defines its identity in the periodic table.
Definition of Atomic Number
- The atomic number is defined as the number of protons in the nucleus of an atom.
- It is denoted by the symbol 'Z'.
Significance of Protons
- Protons are positively charged particles found in the nucleus.
- The number of protons determines the element's chemical properties and its place in the periodic table.
Relation to Electrons
- In a neutral atom, the number of electrons equals the number of protons.
- This balance of charges ensures the atom is electrically neutral.
Neutrons and Nucleons
- Neutrons are neutral particles in the nucleus and do not affect the atomic number.
- The total number of protons and neutrons in an atom is known as the mass number, which is different from the atomic number.
Why Option 'C' is Correct
- Option 'C', stating that the atomic number equals the number of protons in the nucleus, is accurate.
- This definition directly correlates with the identity of the element.
Summary
- The atomic number is fundamental for identifying elements.
- It directly influences an element's chemical behavior and its placement in the periodic table.
- Understanding the atomic number helps in grasping concepts in chemistry and atomic structure.
Mass number of element is –- a)Number of protons in its nucleus
- b)Number of electrons and protons in the atom
- c)Number of neutrons and protons in the nucleus
- d)Number of neutrons in the nucleus
Correct answer is option 'C'. Can you explain this answer?
Mass number of element is –
a)
Number of protons in its nucleus
b)
Number of electrons and protons in the atom
c)
Number of neutrons and protons in the nucleus
d)
Number of neutrons in the nucleus
| | Shaheenpreet Kaul. answered |
The mass number is sum. Of protons and neutrons in the nucleus because mass of electrons is so much less that it is almost neglectable. So when we calculate mass we only take protons and neutrons.
The number of valence electrons in a sulfide ion, S2– is- a)8
- b)9
- c)10
- d)16
Correct answer is option 'A'. Can you explain this answer?
The number of valence electrons in a sulfide ion, S2– is
a)
8
b)
9
c)
10
d)
16
 | Prerna Chavan answered |
Understanding Valence Electrons in Sulphide Ion (S2-)
Valence electrons are the outermost electrons of an atom and play a crucial role in chemical bonding. To determine the number of valence electrons in a sulphide ion (S2-), we need to analyze the sulfur atom first.
Valence Electrons in Sulfur
- Sulfur (S) is in Group 16 of the periodic table.
- It has 6 valence electrons in its neutral state.
Effect of Ion Formation
- When sulfur forms a sulphide ion (S2-), it gains 2 additional electrons.
- The negative charge (2-) indicates that the sulfur atom has accepted 2 electrons to achieve a stable electronic configuration.
Calculating Valence Electrons in S2-
- Start with the 6 valence electrons from neutral sulfur.
- Add the 2 extra electrons gained during ion formation.
Thus, the total number of valence electrons in the sulphide ion (S2-) is:
- 6 (from neutral sulfur) + 2 (gained electrons) = 8 valence electrons.
Conclusion
- The correct answer is option 'A', which states that the number of valence electrons in the sulphide ion (S2-) is 8.
- This configuration allows the sulphide ion to achieve a more stable state, similar to the noble gases.
Understanding these concepts is essential for grasping how elements interact and bond in chemical reactions!
Valence electrons are the outermost electrons of an atom and play a crucial role in chemical bonding. To determine the number of valence electrons in a sulphide ion (S2-), we need to analyze the sulfur atom first.
Valence Electrons in Sulfur
- Sulfur (S) is in Group 16 of the periodic table.
- It has 6 valence electrons in its neutral state.
Effect of Ion Formation
- When sulfur forms a sulphide ion (S2-), it gains 2 additional electrons.
- The negative charge (2-) indicates that the sulfur atom has accepted 2 electrons to achieve a stable electronic configuration.
Calculating Valence Electrons in S2-
- Start with the 6 valence electrons from neutral sulfur.
- Add the 2 extra electrons gained during ion formation.
Thus, the total number of valence electrons in the sulphide ion (S2-) is:
- 6 (from neutral sulfur) + 2 (gained electrons) = 8 valence electrons.
Conclusion
- The correct answer is option 'A', which states that the number of valence electrons in the sulphide ion (S2-) is 8.
- This configuration allows the sulphide ion to achieve a more stable state, similar to the noble gases.
Understanding these concepts is essential for grasping how elements interact and bond in chemical reactions!
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : The atoms of different elements having same mass number but different atomic numbers are known as isobars.Reason : The sum of protons and neutrons, in the isobars is always different.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Assertion (A) is false but reason (R) is true.
Correct answer is option 'C'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : The atoms of different elements having same mass number but different atomic numbers are known as isobars.
Reason : The sum of protons and neutrons, in the isobars is always different.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Assertion (A) is false but reason (R) is true.
| | Avinash Patel answered |
Sum of protons and neutrons is known as mass number which is same for isobars.
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Isobars are identical in chemical properties.Reason : Isobars have same atomic number.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Both assertion and reason are incorrect.
Correct answer is option 'D'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Isobars are identical in chemical properties.
Reason : Isobars have same atomic number.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Both assertion and reason are incorrect.
 | Radha Iyer answered |
Isobars are not identical in chemical properties because they have same mass number and different atomic numbers.
When a gas at reduced pressure is subjected to an electric discharge, the rays orignating from the negative electrode are–- a)Anode rays
- b)Cathode rays
- c)x-rays
- d)Radiation ray
Correct answer is option 'A'. Can you explain this answer?
When a gas at reduced pressure is subjected to an electric discharge, the rays orignating from the negative electrode are–
a)
Anode rays
b)
Cathode rays
c)
x-rays
d)
Radiation ray
 | Vikas Kapoor answered |
Cathode ray, stream of electrons leaving the negative electrode (cathode) in a discharge tube containing a gas at low pressure, or electrons emitted by a heated filament in certain electron tubes. Cathode rays focused on a hard target (anticathode) produce X-rays or focused on a small object in a vacuum generate very high temperatures (cathode-ray furnace). When cathode rays strike certain molecules used to coat a cathode screen, they cause the molecules (and hence the screen) to emit light.
The isotope deuterium of hydrogen has- a)No neutrons and one proton
- b)One neutrons and two protons
- c)One electron and two neutron
- d)One proton and one neutron
Correct answer is option 'D'. Can you explain this answer?
The isotope deuterium of hydrogen has
a)
No neutrons and one proton
b)
One neutrons and two protons
c)
One electron and two neutron
d)
One proton and one neutron
 | Betu Betu answered |
Because we know that isotopes have same atomic no but different atomic mass . the isotopes of hydrogen have same no of proton because no of proton = atomic no and and atomic no do not change in isotopes but the no of electron will change due to change in its mass
Fundamental particle of atomic nucleus is–- a)p, e-
- b)p, n, e
- c)p, n
- d)n , e
Correct answer is option 'C'. Can you explain this answer?
Fundamental particle of atomic nucleus is–
a)
p, e-
b)
p, n, e
c)
p, n
d)
n , e
 | Dhruva Mohan answered |
Opt.b proton
neutron
electron
neutron
electron
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Atom is electrically neutral.Reason : A neutral particle, neutron is present in the nucleus of atom.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Assertion (A) is false but reason (R) is true.
Correct answer is option 'B'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Atom is electrically neutral.
Reason : A neutral particle, neutron is present in the nucleus of atom.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Assertion (A) is false but reason (R) is true.
| | Aditi Sharma answered |
Atom is electrically neutral because the number of protons (positively charged particle) is equal to the number of electrons (negatively charged particle).
Neutron is a fundamental particle which have–- a)+1 unit charge and 1 unit mass
- b)No charge and 1 unit mass
- c)Have no charge and mass
- d)Have –1 unit charge and 1 unit mass
Correct answer is option 'B'. Can you explain this answer?
Neutron is a fundamental particle which have–
a)
+1 unit charge and 1 unit mass
b)
No charge and 1 unit mass
c)
Have no charge and mass
d)
Have –1 unit charge and 1 unit mass
| | Mira Sharma answered |
Neutron is a fundamental particle which have–
There are four options given to choose from regarding the charge and mass of a neutron. Let's analyze each option to determine the correct answer.
Option A: 1 unit charge and 1 unit mass
- A neutron has no charge, so this option is incorrect.
Option B: No charge and 1 unit mass
- This option correctly states that a neutron has no charge. Neutrons are electrically neutral particles.
- Neutrons do have mass, with a mass of approximately 1 atomic mass unit (u) or 1.67 × 10^-27 kg.
- Therefore, option B is correct.
Option C: Have no charge and mass
- This option is incorrect as it implies that a neutron has no mass. However, neutrons do have mass.
Option D: Have –1 unit charge and 1 unit mass
- This option is incorrect as it states that a neutron has a negative charge. Neutrons are electrically neutral and do not possess any charge.
Therefore, the correct answer is option B: Neutrons have no charge and 1 unit mass.
There are four options given to choose from regarding the charge and mass of a neutron. Let's analyze each option to determine the correct answer.
Option A: 1 unit charge and 1 unit mass
- A neutron has no charge, so this option is incorrect.
Option B: No charge and 1 unit mass
- This option correctly states that a neutron has no charge. Neutrons are electrically neutral particles.
- Neutrons do have mass, with a mass of approximately 1 atomic mass unit (u) or 1.67 × 10^-27 kg.
- Therefore, option B is correct.
Option C: Have no charge and mass
- This option is incorrect as it implies that a neutron has no mass. However, neutrons do have mass.
Option D: Have –1 unit charge and 1 unit mass
- This option is incorrect as it states that a neutron has a negative charge. Neutrons are electrically neutral and do not possess any charge.
Therefore, the correct answer is option B: Neutrons have no charge and 1 unit mass.
An atom which has a mass number of 14 or 8 neutrons is–- a)Isotope of oxygen
- b)Isobar of oxygen
- c)Isotope of carbon
- d)Isobar of carbon
Correct answer is option 'C'. Can you explain this answer?
An atom which has a mass number of 14 or 8 neutrons is–
a)
Isotope of oxygen
b)
Isobar of oxygen
c)
Isotope of carbon
d)
Isobar of carbon
| | Gaurav Kumar answered |
Isotopes are the atoms of the same element with similar atomic number but different atomic mass.The elements of isotopes share same chemical properties but different physical properties
Which species does not contain neutron –- a)H
- b)Li+2
- c)C
- d)O
Correct answer is option 'A'. Can you explain this answer?
Which species does not contain neutron –
a)
H
b)
Li+2
c)
C
d)
O
| | Priya Shah answered |
No species exists without neutrons. All atoms have at least one neutron in their nucleus, except for the hydrogen-1 isotope, which does not have any neutrons.
The mass number of two atoms X and Y is the same (40 each)but their atomic number are different (being 20 and 18, respectively). X and Y are examples of- a)Isotopes
- b)Isobars
- c)Solid and liquid
- d)Chemically similar atoms
Correct answer is option 'B'. Can you explain this answer?
The mass number of two atoms X and Y is the same (40 each)but their atomic number are different (being 20 and 18, respectively). X and Y are examples of
a)
Isotopes
b)
Isobars
c)
Solid and liquid
d)
Chemically similar atoms
| | Shilpa Choudhury answered |
Elements with atomic number 18 and 20 are Argon and potassium respectively.
Isobar compounds have the same mass number but the different atomic number and chemical properties depend upon the number of electrons so isobars have different chemical properties.
Which of the following represents the correct electron distribution in magnesium ions?- a)2, 8
- b)2,8, 1
- c)2, 8, 2
- d)2, 8, 3
Correct answer is option 'A'. Can you explain this answer?
Which of the following represents the correct electron distribution in magnesium ions?
a)
2, 8
b)
2,8, 1
c)
2, 8, 2
d)
2, 8, 3
| | Shilpa Choudhury answered |
Electronic configuration of 12Mg atom is = 2, 8, 2
Electronic configuration of Mg2+ ion is = 2, 8, because 2 positive charges means it loses two electrons.
There are four elements P, Q, R and S having atomic numbers of 4, 18, 10 and 16, respectively. The element which can exhibit covalency as well as electrovalency will be- a)S
- b)R
- c)Q
- d)P
Correct answer is option 'A'. Can you explain this answer?
There are four elements P, Q, R and S having atomic numbers of 4, 18, 10 and 16, respectively. The element which can exhibit covalency as well as electrovalency will be
a)
S
b)
R
c)
Q
d)
P
 | Nidhi Reddy answered |
Covalency and electrovalency are two types of chemical bonding. Covalent bonding involves the sharing of electrons between atoms, while electrovalent bonding involves the transfer of electrons from one atom to another.
In order to determine which element can exhibit both covalency and electrovalency, we need to consider the electronic configuration and valency of each element.
Electronic Configuration:
- Element P has an atomic number of 4, which means it has 4 electrons. Its electronic configuration is 2, 2.
- Element Q has an atomic number of 18, which means it has 18 electrons. Its electronic configuration is 2, 8, 8.
- Element R has an atomic number of 10, which means it has 10 electrons. Its electronic configuration is 2, 8.
- Element S has an atomic number of 16, which means it has 16 electrons. Its electronic configuration is 2, 8, 6.
Valency:
- The valency of an element depends on the number of electrons it needs to gain, lose, or share to achieve a stable electron configuration.
- Element P has a valency of 4, as it needs to gain 4 electrons to achieve a stable configuration.
- Element Q has a valency of 8, as it needs to gain 8 electrons to achieve a stable configuration.
- Element R has a valency of 2, as it needs to gain 2 electrons to achieve a stable configuration.
- Element S has a valency of 6, as it needs to gain 2 electrons to achieve a stable configuration.
Analysis:
- Elements P and R have a valency of 4 and 2, respectively. These valencies suggest that they can exhibit covalency, as they have electrons available for sharing.
- Elements Q and S have valencies of 8 and 6, respectively. These valencies suggest that they can exhibit electrovalency, as they have electrons available for transfer.
Conclusion:
Based on the analysis, the element that can exhibit both covalency and electrovalency is element S (atomic number 16). Element S has a valency of 6, suggesting it can exhibit electrovalency, and it also has electrons available for sharing, indicating it can exhibit covalency as well. Therefore, the correct answer is option 'A'.
In order to determine which element can exhibit both covalency and electrovalency, we need to consider the electronic configuration and valency of each element.
Electronic Configuration:
- Element P has an atomic number of 4, which means it has 4 electrons. Its electronic configuration is 2, 2.
- Element Q has an atomic number of 18, which means it has 18 electrons. Its electronic configuration is 2, 8, 8.
- Element R has an atomic number of 10, which means it has 10 electrons. Its electronic configuration is 2, 8.
- Element S has an atomic number of 16, which means it has 16 electrons. Its electronic configuration is 2, 8, 6.
Valency:
- The valency of an element depends on the number of electrons it needs to gain, lose, or share to achieve a stable electron configuration.
- Element P has a valency of 4, as it needs to gain 4 electrons to achieve a stable configuration.
- Element Q has a valency of 8, as it needs to gain 8 electrons to achieve a stable configuration.
- Element R has a valency of 2, as it needs to gain 2 electrons to achieve a stable configuration.
- Element S has a valency of 6, as it needs to gain 2 electrons to achieve a stable configuration.
Analysis:
- Elements P and R have a valency of 4 and 2, respectively. These valencies suggest that they can exhibit covalency, as they have electrons available for sharing.
- Elements Q and S have valencies of 8 and 6, respectively. These valencies suggest that they can exhibit electrovalency, as they have electrons available for transfer.
Conclusion:
Based on the analysis, the element that can exhibit both covalency and electrovalency is element S (atomic number 16). Element S has a valency of 6, suggesting it can exhibit electrovalency, and it also has electrons available for sharing, indicating it can exhibit covalency as well. Therefore, the correct answer is option 'A'.
Atomic models have been improved over the years. Arrange the following atomic models in the order of their chronological order.
(i) Rutherford’s atomic model
(ii) Thomson’s atomic model
(iii) Bohr’s atomic model- a)(i), (ii) and (iii)
- b)(ii), (iii) and (i)
- c)(ii), (i) and (iii)
- d)(iii), (ii) and (i)
Correct answer is option 'C'. Can you explain this answer?
Atomic models have been improved over the years. Arrange the following atomic models in the order of their chronological order.
(i) Rutherford’s atomic model
(ii) Thomson’s atomic model
(iii) Bohr’s atomic model
(i) Rutherford’s atomic model
(ii) Thomson’s atomic model
(iii) Bohr’s atomic model
a)
(i), (ii) and (iii)
b)
(ii), (iii) and (i)
c)
(ii), (i) and (iii)
d)
(iii), (ii) and (i)
| | Sagarika Joshi answered |
Model (ii) Bohr model (iii) Thomson model
(iii) Thomson model, (i) Rutherford model, (ii) Bohr model
(iii) Thomson model, (i) Rutherford model, (ii) Bohr model
The electron should be filled in the orbital in accordance with the increasing order of their energy. This statement
is related with- a)Affbau principle
- b)Pauli principle
- c)Hund's principle
- d)Plank's rules
Correct answer is option 'A'. Can you explain this answer?
The electron should be filled in the orbital in accordance with the increasing order of their energy. This statement
is related with
is related with
a)
Affbau principle
b)
Pauli principle
c)
Hund's principle
d)
Plank's rules
| | Rahul Choudhury answered |
This statement is related with Aufbau principle.
According to Aufbau principle (also known as (n+l) rule), electrons are filled in different orbitals from lower (n+l) value orbital to higher (n+l) value orbital.
In case (n+l) value is same, electron is filled first in orbital with lower value of n.
According to Aufbau principle (also known as (n+l) rule), electrons are filled in different orbitals from lower (n+l) value orbital to higher (n+l) value orbital.
In case (n+l) value is same, electron is filled first in orbital with lower value of n.
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : In Rutherford’s gold foil experiment, very few α -particles are deflected back.Reason : Nucleus present inside the atom is heavy.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Assertion (A) is false but reason (R) is true.
Correct answer is option 'B'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : In Rutherford’s gold foil experiment, very few α -particles are deflected back.
Reason : Nucleus present inside the atom is heavy.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Assertion (A) is false but reason (R) is true.
| | Amit Kumar answered |
Nucleus present inside the atom is heavy but small.
What are cathode rays?- a)Positively charged
- b)Negatively charged
- c)Neutral
- d)All of these
Correct answer is option 'B'. Can you explain this answer?
What are cathode rays?
a)
Positively charged
b)
Negatively charged
c)
Neutral
d)
All of these
| | Shilpa Choudhury answered |
Cathode rays (also called an electron beam or an e-beam) are streams of electrons observed in vacuum tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, the glass opposite the negative electrode is observed to glow from electrons emitted from the cathode.
Which of the following statement is always correct?- a)an atom has equal number of electrons, protons and neutrons
- b)an atom has equal number of neutrons
- c)an atom has equal number of electrons and neutrons
- d)an atom has equal number of electrons and protons
Correct answer is option 'D'. Can you explain this answer?
Which of the following statement is always correct?
a)
an atom has equal number of electrons, protons and neutrons
b)
an atom has equal number of neutrons
c)
an atom has equal number of electrons and neutrons
d)
an atom has equal number of electrons and protons
| | Shilpa Choudhury answered |
An atom is electrically neutral because the number of protons is always equal to a number of electrons. Hence option (d) is right.
Atomic number = Number of proton(p) = Number of electron(e)
Statement 1 - According to the Rutherford model of the atom, an electron in a circular orbit experiences acceleration and, as a result, radiates energy, leading to a loss of energy over time.
Statement 2 - According to the Rutherford model of the atom, this energy loss would cause the electron to spiral into the nucleus, making atoms inherently unstable.Which of the statements given above is/are correct?- a)1 Only
- b)2 only
- c)Both 1 and 2
- d)Neither 1 nor 2
Correct answer is option 'C'. Can you explain this answer?
Statement 1 - According to the Rutherford model of the atom, an electron in a circular orbit experiences acceleration and, as a result, radiates energy, leading to a loss of energy over time.
Statement 2 - According to the Rutherford model of the atom, this energy loss would cause the electron to spiral into the nucleus, making atoms inherently unstable.
Statement 2 - According to the Rutherford model of the atom, this energy loss would cause the electron to spiral into the nucleus, making atoms inherently unstable.
Which of the statements given above is/are correct?
a)
1 Only
b)
2 only
c)
Both 1 and 2
d)
Neither 1 nor 2
 | Imk Pathshala answered |
Both statements describe the limitations of the Rutherford model and how they lead to instability in atoms, which was later addressed by the Bohr model.
Statement 1: This is consistent with Rutherford's model, where he proposed that the electron orbits the nucleus in a circular path. Since the electron is accelerating in this orbit, classical electromagnetic theory states that it should emit radiation and lose energy over time. This leads to the electron's energy decreasing as it radiates energy.
Statement 2: This follows logically from Statement 1. Since the electron in Rutherford's model radiates energy and loses it over time, it would move closer to the nucleus as its energy decreases. Eventually, the electron would spiral into the nucleus, causing the atom to collapse. This would make the atom unstable in the Rutherford model.
Statement 2: This follows logically from Statement 1. Since the electron in Rutherford's model radiates energy and loses it over time, it would move closer to the nucleus as its energy decreases. Eventually, the electron would spiral into the nucleus, causing the atom to collapse. This would make the atom unstable in the Rutherford model.
An isotope of an element has 11 protons and 13 neutrons. What is the mass number of another isotope of the same element with 14 neutrons?- a)24
- b)25
- c)11
- d)14
Correct answer is option 'B'. Can you explain this answer?
An isotope of an element has 11 protons and 13 neutrons. What is the mass number of another isotope of the same element with 14 neutrons?
a)
24
b)
25
c)
11
d)
14
| | Let's Tute answered |
An isotope of an element has 11 protons and 13 neutrons. The mass number is the total of protons and neutrons.
- Mass number = Protons + Neutrons
- For this isotope: 11 + 13 = 24
Now, for another isotope of the same element with 14 neutrons:
- Mass number = 11 + 14 = 25
The correct answer is 25.
The maximum number of electrons that can be accommodated in third shell ( n = 3) is:- a)2
- b)8
- c)18
- d)10
Correct answer is option 'C'. Can you explain this answer?
The maximum number of electrons that can be accommodated in third shell ( n = 3) is:
a)
2
b)
8
c)
18
d)
10
| | Sreemoyee Bajaj answered |
**Explanation:**
The maximum number of electrons that can be accommodated in a shell is given by the formula 2n², where 'n' is the principal quantum number of the shell.
In the case of the third shell, n = 3. Therefore, the maximum number of electrons that can be accommodated in the third shell is:
2(3)² = 2(9) = 18
**- Electron distribution in shells:**
In an atom, electrons are distributed in different shells based on their energy levels. The shells are numbered starting from the innermost shell, which is designated as the first shell (n = 1), followed by the second shell (n = 2), and so on.
Each shell can hold a maximum number of electrons based on its principal quantum number (n). The electron distribution in shells is as follows:
- **First shell (n = 1):** This shell can hold a maximum of 2 electrons.
- **Second shell (n = 2):** This shell can hold a maximum of 2(2)² = 8 electrons.
- **Third shell (n = 3):** This shell can hold a maximum of 2(3)² = 18 electrons.
- **Fourth shell (n = 4):** This shell can hold a maximum of 2(4)² = 32 electrons.
- **Fifth shell (n = 5):** This shell can hold a maximum of 2(5)² = 50 electrons.
- **And so on...**
It is important to note that as the principal quantum number increases, the maximum number of electrons that can be accommodated in a shell also increases. This is because higher energy levels can accommodate more electrons.
Thus, the correct answer is option 'C' (18) as the maximum number of electrons that can be accommodated in the third shell (n = 3) is 18.
The maximum number of electrons that can be accommodated in a shell is given by the formula 2n², where 'n' is the principal quantum number of the shell.
In the case of the third shell, n = 3. Therefore, the maximum number of electrons that can be accommodated in the third shell is:
2(3)² = 2(9) = 18
**- Electron distribution in shells:**
In an atom, electrons are distributed in different shells based on their energy levels. The shells are numbered starting from the innermost shell, which is designated as the first shell (n = 1), followed by the second shell (n = 2), and so on.
Each shell can hold a maximum number of electrons based on its principal quantum number (n). The electron distribution in shells is as follows:
- **First shell (n = 1):** This shell can hold a maximum of 2 electrons.
- **Second shell (n = 2):** This shell can hold a maximum of 2(2)² = 8 electrons.
- **Third shell (n = 3):** This shell can hold a maximum of 2(3)² = 18 electrons.
- **Fourth shell (n = 4):** This shell can hold a maximum of 2(4)² = 32 electrons.
- **Fifth shell (n = 5):** This shell can hold a maximum of 2(5)² = 50 electrons.
- **And so on...**
It is important to note that as the principal quantum number increases, the maximum number of electrons that can be accommodated in a shell also increases. This is because higher energy levels can accommodate more electrons.
Thus, the correct answer is option 'C' (18) as the maximum number of electrons that can be accommodated in the third shell (n = 3) is 18.
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Bohr’s orbits are called stationary orbits.Reason : Electrons remain stationary in these orbits for sometime.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Assertion (A) is false but reason (R) is true.
Correct answer is option 'C'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Bohr’s orbits are called stationary orbits.
Reason : Electrons remain stationary in these orbits for sometime.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Assertion (A) is false but reason (R) is true.
| | Swati Verma answered |
Electrons in different orbits have fixed energies.
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Isotopes of an element show different valencies.Reason : Isotopes have different atomic numbers.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Both A and R are False
Correct answer is option 'D'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Isotopes of an element show different valencies.
Reason : Isotopes have different atomic numbers.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Both A and R are False
 | Ishan Choudhury answered |
Isotopes have the same number of electrons. Hence, their valencies do not differ. Isotopes have the same atomic number but different atomic mass numbers: The total number of protons present in the atomic nucleus is known as its atomic number whereas the mass number is defined as the total number of protons and neutrons present in the atomic nucleus.
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Isotopes are electrically neutral.Reason : Isotopes are species with same mass number but different atomic numbers.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Assertion (A) is false but reason (R) is true.
Correct answer is option 'C'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Isotopes are electrically neutral.
Reason : Isotopes are species with same mass number but different atomic numbers.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Assertion (A) is false but reason (R) is true.
| | Vivek Rana answered |
Isotopes are species with same atomic number but different mass numbers.
Lighest particle is –- a)Neutron
- b)Electron
- c)Proton
- d)None of these
Correct answer is option 'B'. Can you explain this answer?
Lighest particle is –
a)
Neutron
b)
Electron
c)
Proton
d)
None of these
 | Priya Dasgupta answered |
The lightest particle known to exist is the neutrino. Neutrinos are subatomic particles that have a very small mass and do not have an electric charge. They are extremely difficult to detect and interact very weakly with other particles, which makes them elusive and challenging to study.
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : A few positively charged a -particles are deflected in Rutherford’s experiment.Reason : Most of the space in the atom is empty.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Assertion (A) is false but reason (R) is true.
Correct answer is option 'B'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : A few positively charged a -particles are deflected in Rutherford’s experiment.
Reason : Most of the space in the atom is empty.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Assertion (A) is false but reason (R) is true.
| | Advait Desai answered |
Assertion (A): A few positively charged alpha particles are deflected in Rutherford's experiment.
Reason (R): Most of the space in the atom is empty.
Explanation:
In Rutherford's experiment, alpha particles were bombarded onto a thin gold foil. According to the prevailing 'plum pudding' model of the atom, it was believed that the positive charge and mass of the atom were uniformly distributed throughout the atom. In this model, it was expected that the alpha particles would pass straight through the foil with minimal deflection.
However, the actual results of the experiment showed that some of the alpha particles were deflected at large angles or even bounced back. This observation led Rutherford to propose a new model of the atom, known as the nuclear model. In this model, he suggested that the positive charge and most of the mass of the atom are concentrated in a tiny, dense nucleus at the center, while the electrons orbit the nucleus.
Assertion (A) is true because in Rutherford's experiment, a few alpha particles were indeed deflected from their initial paths.
Reason (R) is also true because the deflection of alpha particles in Rutherford's experiment provided evidence for the existence of a tiny, dense nucleus within the atom. This implies that most of the space within the atom is empty, with the electrons occupying a relatively large volume compared to the nucleus.
Reason (R) is the correct explanation of assertion (A) because the deflection of alpha particles can be attributed to the repulsive electrostatic forces between the positively charged alpha particles and the positively charged nucleus. Since most of the space in the atom is empty, the chances of an alpha particle coming close to the nucleus and experiencing a significant deflection are relatively low.
Therefore, the correct answer is option B - Both assertion (A) and reason (R) are true, but reason (R) is not the correct explanation of assertion (A).
Reason (R): Most of the space in the atom is empty.
Explanation:
In Rutherford's experiment, alpha particles were bombarded onto a thin gold foil. According to the prevailing 'plum pudding' model of the atom, it was believed that the positive charge and mass of the atom were uniformly distributed throughout the atom. In this model, it was expected that the alpha particles would pass straight through the foil with minimal deflection.
However, the actual results of the experiment showed that some of the alpha particles were deflected at large angles or even bounced back. This observation led Rutherford to propose a new model of the atom, known as the nuclear model. In this model, he suggested that the positive charge and most of the mass of the atom are concentrated in a tiny, dense nucleus at the center, while the electrons orbit the nucleus.
Assertion (A) is true because in Rutherford's experiment, a few alpha particles were indeed deflected from their initial paths.
Reason (R) is also true because the deflection of alpha particles in Rutherford's experiment provided evidence for the existence of a tiny, dense nucleus within the atom. This implies that most of the space within the atom is empty, with the electrons occupying a relatively large volume compared to the nucleus.
Reason (R) is the correct explanation of assertion (A) because the deflection of alpha particles can be attributed to the repulsive electrostatic forces between the positively charged alpha particles and the positively charged nucleus. Since most of the space in the atom is empty, the chances of an alpha particle coming close to the nucleus and experiencing a significant deflection are relatively low.
Therefore, the correct answer is option B - Both assertion (A) and reason (R) are true, but reason (R) is not the correct explanation of assertion (A).
When alpha-particles are sent through a thin metal foil, most of them go straight through the foil because - a)alpha-particles are positively charged
- b)alpha-particles are much smaller than electrons
- c)alpha-particles move with low velocity
- d)most part of the atom is empty
Correct answer is option 'D'. Can you explain this answer?
When alpha-particles are sent through a thin metal foil, most of them go straight through the foil because
a)
alpha-particles are positively charged
b)
alpha-particles are much smaller than electrons
c)
alpha-particles move with low velocity
d)
most part of the atom is empty
 | Kritika Bose answered |
When alpha particles are sent through at thin metal foil, most of them go straight through the foil because most part of the atom is empty space. In other words, there is no obstruction in the path of alpha particles.
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Isotopes are electrically neutral.Reason : Isotopes of an element have equal number of protons and electrons.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Assertion (A) is false but reason (R) is true.
Correct answer is option 'A'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Isotopes are electrically neutral.
Reason : Isotopes of an element have equal number of protons and electrons.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Assertion (A) is false but reason (R) is true.
| | Prarthana Shah answered |
Assertion: Isotopes are electrically neutral.
Reason: Isotopes of an element have equal number of protons and electrons.
Explanation:
Isotopes are atoms of the same element that have different numbers of neutrons in their nucleus. The number of neutrons in an atom does not affect its electrical charge because neutrons are electrically neutral. Therefore, the assertion that isotopes are electrically neutral is correct.
The reason given for this assertion is also correct. All atoms have an equal number of protons and electrons in order to maintain electrical neutrality. Protons have a positive charge, while electrons have a negative charge. The positive charge of the protons is balanced by the negative charge of the electrons, resulting in an overall neutral charge for the atom.
Since isotopes have the same number of protons as the original element, they also have an equal number of electrons. This maintains the electrical neutrality of the atom, regardless of the number of neutrons present.
Conclusion:
Both the assertion and the reason are true, and the reason provides the correct explanation for the assertion. Therefore, option A is the correct answer.
Reason: Isotopes of an element have equal number of protons and electrons.
Explanation:
Isotopes are atoms of the same element that have different numbers of neutrons in their nucleus. The number of neutrons in an atom does not affect its electrical charge because neutrons are electrically neutral. Therefore, the assertion that isotopes are electrically neutral is correct.
The reason given for this assertion is also correct. All atoms have an equal number of protons and electrons in order to maintain electrical neutrality. Protons have a positive charge, while electrons have a negative charge. The positive charge of the protons is balanced by the negative charge of the electrons, resulting in an overall neutral charge for the atom.
Since isotopes have the same number of protons as the original element, they also have an equal number of electrons. This maintains the electrical neutrality of the atom, regardless of the number of neutrons present.
Conclusion:
Both the assertion and the reason are true, and the reason provides the correct explanation for the assertion. Therefore, option A is the correct answer.
What analogy did Thomson use to describe his model of the atom?- a)A sandwich
- b)A Christmas pudding
- c)A balloon
- d)A fruit salad
Correct answer is option 'B'. Can you explain this answer?
What analogy did Thomson use to describe his model of the atom?
a)
A sandwich
b)
A Christmas pudding
c)
A balloon
d)
A fruit salad
 | Academic Studio answered |
Thomson compared his model of the atom to a Christmas pudding, where the positive charge is the pudding itself and the electrons are the currants embedded within it.
The maximum number of electrons that can be accomodate in the nth level is–- a)n2
- b)2n2
- c)4n2
- d)n
Correct answer is option 'B'. Can you explain this answer?
The maximum number of electrons that can be accomodate in the nth level is–
a)
n2
b)
2n2
c)
4n2
d)
n
| | Let's Tute answered |
According to the question, we need to determine the maximum number of electrons that can be accommodated in the nth level.
To solve this problem, we can use the formula for the maximum number of electrons in a specific energy level. The formula is given by:
Maximum number of electrons = 2n^2
Where:
- n represents the energy level or the principal quantum number.
Let's break down the solution into steps:
Step 1: Substitute the value of n into the formula.
- We are given the value of n as the nth level.
Step 2: Calculate the maximum number of electrons.
- Square the value of n (n^2).
- Multiply the squared value by 2 (2n^2).
Step 3: Determine the final answer.
- The maximum number of electrons that can be accommodated in the nth level is equal to the result obtained from step 2.
Therefore, the correct answer is option B: 2n^2.
To solve this problem, we can use the formula for the maximum number of electrons in a specific energy level. The formula is given by:
Maximum number of electrons = 2n^2
Where:
- n represents the energy level or the principal quantum number.
Let's break down the solution into steps:
Step 1: Substitute the value of n into the formula.
- We are given the value of n as the nth level.
Step 2: Calculate the maximum number of electrons.
- Square the value of n (n^2).
- Multiply the squared value by 2 (2n^2).
Step 3: Determine the final answer.
- The maximum number of electrons that can be accommodated in the nth level is equal to the result obtained from step 2.
Therefore, the correct answer is option B: 2n^2.
In the Thomson’s model of atoms, which of the following statements are correct?
(i) The mass of the atoms is assumed to be uniformly distributed over the atom.
(ii) The positive charge is uniformly distributed over the space.
(iii) The electrons are uniformly distributed in the positively charged sphere.
(iv) The electrons attract each other to stabilise the atom.- a)(i), (ii) and (iii)
- b)(i) and (iii)
- c)(i) and (iv)
- d)(i), (iii) and (iv)
Correct answer is option 'B'. Can you explain this answer?
In the Thomson’s model of atoms, which of the following statements are correct?
(i) The mass of the atoms is assumed to be uniformly distributed over the atom.
(ii) The positive charge is uniformly distributed over the space.
(iii) The electrons are uniformly distributed in the positively charged sphere.
(iv) The electrons attract each other to stabilise the atom.
(i) The mass of the atoms is assumed to be uniformly distributed over the atom.
(ii) The positive charge is uniformly distributed over the space.
(iii) The electrons are uniformly distributed in the positively charged sphere.
(iv) The electrons attract each other to stabilise the atom.
a)
(i), (ii) and (iii)
b)
(i) and (iii)
c)
(i) and (iv)
d)
(i), (iii) and (iv)
 | EduRev Class 9 answered |
Statement (i): The mass of the atom is assumed to be uniformly distributed over the atom.
- Correct. According to Thomson, the atom is a uniformly distributed mass.
Statement (iii): The electrons are uniformly distributed in the positively charged sphere.
- Correct. Electrons are embedded in the positively charged sphere like "plums in a pudding."
Rutherford’s a-particle scattering experiment showed that
(i) electrons have negative charge
(ii) the mass and positive charge of the atom is concentrated in the nucleus
(iii) neutron exists in the nucleus
(iv) most of the space in atom is empty
Which of the above statements are correct?- a)(i) and (ii)
- b)(ii) and (iv)
- c)(i) and (iii)
- d)All of these
Correct answer is option 'B'. Can you explain this answer?
Rutherford’s a-particle scattering experiment showed that
(i) electrons have negative charge
(ii) the mass and positive charge of the atom is concentrated in the nucleus
(iii) neutron exists in the nucleus
(iv) most of the space in atom is empty
Which of the above statements are correct?
(i) electrons have negative charge
(ii) the mass and positive charge of the atom is concentrated in the nucleus
(iii) neutron exists in the nucleus
(iv) most of the space in atom is empty
Which of the above statements are correct?
a)
(i) and (ii)
b)
(ii) and (iv)
c)
(i) and (iii)
d)
All of these
| | Rajdeep Goyal answered |
Points (ii) and (iv) are correct. An atom consists of a positively charged, dense and very small nucleus which have all the protons and neutrons. Positive charge is due to protons, as neutrons have no charge. Most of the space is empty because most of the alpha particles pass straight through the gold foil without any deflection.
Electrons have negative charge, it was explained by Thomson. The existance of neutron was discovered by Chadwick.
Electrons have negative charge, it was explained by Thomson. The existance of neutron was discovered by Chadwick.
An element U has 13 electrons. According to Bohr’s model, what is the electron distribution, and why might Rutherford’s model predict instability for this atom? - a)K: 2, L: 8, M: 3; Electrons would spiral into the nucleus due to energy loss
- b)K: 2, L: 7, M: 4; Electrons would gain energy and escape
- c)K: 2, L: 8, M: 3; Electrons would gain energy and orbit faster
- d)K: 2, L: 8, M: 3; Electrons would remain stable in circular orbits
Correct answer is option 'A'. Can you explain this answer?
An element U has 13 electrons. According to Bohr’s model, what is the electron distribution, and why might Rutherford’s model predict instability for this atom?
a)
K: 2, L: 8, M: 3; Electrons would spiral into the nucleus due to energy loss
b)
K: 2, L: 7, M: 4; Electrons would gain energy and escape
c)
K: 2, L: 8, M: 3; Electrons would gain energy and orbit faster
d)
K: 2, L: 8, M: 3; Electrons would remain stable in circular orbits
| | Let's Tute answered |
Electron distribution for an atom with 13 electrons can be described as follows:
- K shell: 2 electrons
- L shell: 8 electrons
- M shell: 3 electrons
According to Bohr's model, this arrangement is stable. However, Rutherford's model suggests potential instability for the following reasons:
- Electrons may lose energy and spiral into the nucleus.
- There is a risk of electrons gaining energy and escaping.
- Electrons in a circular orbit can become unstable over time.
Identify the Mg atom from the following figures where, n and p represent the number of neutrons and protons respectively.- a)
- b)
- c)
- d)
Correct answer is option 'D'. Can you explain this answer?
Identify the Mg atom from the following figures where, n and p represent the number of neutrons and protons respectively.
a)
b)
c)
d)
 | Saamarth Chauhan answered |
Configuration of ¹²Mg atom = 2,8,3
no. of protons in Mg atom =2+8+2=12
as mass no.of Mg atom is 24 & no.of neutrons=mass no. -no. of protons
no. of neutrons in Mg atom=24-12=12
Thus, option (d) is correct answer
no. of protons in Mg atom =2+8+2=12
as mass no.of Mg atom is 24 & no.of neutrons=mass no. -no. of protons
no. of neutrons in Mg atom=24-12=12
Thus, option (d) is correct answer
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Anions are larger in size than the parent atom.Reason : In an anion, the number of protons in the nucleus is less than the number of electrons moving around it.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Assertion (A) is false but reason (R) is true.
Correct answer is option 'A'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Anions are larger in size than the parent atom.
Reason : In an anion, the number of protons in the nucleus is less than the number of electrons moving around it.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Assertion (A) is false but reason (R) is true.
| | Swati Verma answered |
The size of an anion is larger than its parent atom because anions are formed due to the gain of electrons. When the electrons increase, there are still the same number of protons. The attractive force is thus reduced as there are the same number of protons attracting an increased number of electrons.
Isobars are atoms that have:- a)The same atomic number but different mass numbers
- b)Different mass numbers and atomic numbers
- c)The same mass number but different atomic numbers
- d)Identical proton and neutron numbers
Correct answer is option 'C'. Can you explain this answer?
Isobars are atoms that have:
a)
The same atomic number but different mass numbers
b)
Different mass numbers and atomic numbers
c)
The same mass number but different atomic numbers
d)
Identical proton and neutron numbers
 | Sahil Gupta answered |
Understanding Isobars
Isobars are a concept in nuclear chemistry that refers to atoms of different elements that share the same mass number but have different atomic numbers. Here's a detailed explanation of isobars:
Definition of Isobars
- Isobars are atoms that have:
- The same mass number (the total number of protons and neutrons).
- Different atomic numbers (the number of protons).
Why Option 'C' is Correct
- In option 'C', the statement emphasizes that isobars have:
- Identical mass numbers, meaning they contain the same total number of nucleons (protons + neutrons).
- Different atomic numbers, indicating that they are different elements.
Examples of Isobars
- A classic example of isobars includes:
- Carbon-14 (6 protons and 8 neutrons) and Nitrogen-14 (7 protons and 7 neutrons).
- Both have a mass number of 14 but differ in their atomic numbers (6 for Carbon and 7 for Nitrogen).
Importance of Isobars
- Understanding isobars is crucial in:
- Nuclear chemistry and physics, where the behavior of elements can be analyzed based on their mass numbers.
- Applications in radiocarbon dating and nuclear medicine, where isotopes play a significant role.
In summary, isobars are fascinating as they reveal how elements can be related through their nucleon count while exhibiting different chemical properties due to their unique atomic numbers.
Isobars are a concept in nuclear chemistry that refers to atoms of different elements that share the same mass number but have different atomic numbers. Here's a detailed explanation of isobars:
Definition of Isobars
- Isobars are atoms that have:
- The same mass number (the total number of protons and neutrons).
- Different atomic numbers (the number of protons).
Why Option 'C' is Correct
- In option 'C', the statement emphasizes that isobars have:
- Identical mass numbers, meaning they contain the same total number of nucleons (protons + neutrons).
- Different atomic numbers, indicating that they are different elements.
Examples of Isobars
- A classic example of isobars includes:
- Carbon-14 (6 protons and 8 neutrons) and Nitrogen-14 (7 protons and 7 neutrons).
- Both have a mass number of 14 but differ in their atomic numbers (6 for Carbon and 7 for Nitrogen).
Importance of Isobars
- Understanding isobars is crucial in:
- Nuclear chemistry and physics, where the behavior of elements can be analyzed based on their mass numbers.
- Applications in radiocarbon dating and nuclear medicine, where isotopes play a significant role.
In summary, isobars are fascinating as they reveal how elements can be related through their nucleon count while exhibiting different chemical properties due to their unique atomic numbers.
The atomic size of atom is nearly –- a)10-10 cm
- b)10-6 m
- c)10-7 m
- d)10-10 m
Correct answer is option 'D'. Can you explain this answer?
The atomic size of atom is nearly –
a)
10-10 cm
b)
10-6 m
c)
10-7 m
d)
10-10 m
| | Aravind Kulkarni answered |
The atom is about 10-10 meters (or 10-8 centimeters) in size. This means a row of 10^8 (or 100,000,000)atoms would stretch a centimeter, about the size of your fingernail. Atoms of different elements are different sizes, but 10-10 m can be thought of as a rough value for any atom.
Can you explain the answer of this question below:The first use of quantum theory to explain the structure of atom was made by –
- A:
Heisenberg
- B:
Bohr
- C:
Plank
- D:
Einstein
The answer is B.
The first use of quantum theory to explain the structure of atom was made by –
Heisenberg
Bohr
Plank
Einstein
 | Prachi Rathore answered |
Bohr first made use of quantum theory to explain the structure of atom and proposed that energy of electron in an atom is quantized
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Cathode rays travel in straight lines.Reason : Cathode rays do not penetrate through thin sheets.- a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
- c)Assertion (A) is true but reason (R) is false.
- d)Assertion (A) is false but reason (R) is true.
Correct answer is option 'C'. Can you explain this answer?
Direction: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Cathode rays travel in straight lines.
Reason : Cathode rays do not penetrate through thin sheets.
a)
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
b)
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
c)
Assertion (A) is true but reason (R) is false.
d)
Assertion (A) is false but reason (R) is true.
| | Meera Rana answered |
Cathode rays can penetrate through thin sweets.
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