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All questions of Periodic Table - Periodic Properties and Variations of Properties for Class 10 Exam
P, Q, R are elements of Dobereiner’s triads. If the atomic mass of P is 7 and that of Q is 23, What will be the atomic mass of R?- a)15.0
- b)40.0
- c)30.0
- d)39.0
Correct answer is option 'D'. Can you explain this answer?
P, Q, R are elements of Dobereiner’s triads. If the atomic mass of P is 7 and that of Q is 23, What will be the atomic mass of R?
a)
15.0
b)
40.0
c)
30.0
d)
39.0
|
Gaurav Kumar answered |
In a Dobereiner's traid, the atomic mass of the middle element is roughly the average of the atomic mass of the other 2 elements. Thus,
Atomic mass of Q = (at. mass of P+ at. mass of R) /2
⇒ 23 = 7+ m(R) /2
⇒ 23*2 = 7+ m(R)
⇒ 46 -7 = m(R)
⇒ atomic mass of R = 39
Atomic mass of Q = (at. mass of P+ at. mass of R) /2
⇒ 23 = 7+ m(R) /2
⇒ 23*2 = 7+ m(R)
⇒ 46 -7 = m(R)
⇒ atomic mass of R = 39
How many elements are placed in lanthanide and actinide series?- a)57, 89
- b)14, 14
- c)89, 57
- d)14, 16
Correct answer is option 'B'. Can you explain this answer?
How many elements are placed in lanthanide and actinide series?
a)
57, 89
b)
14, 14
c)
89, 57
d)
14, 16
|
Neha Patel answered |
14 elements
The same holds for the actinide series that runs from atomic number 90 through to number 103, again 14 elements. Thus, as you move from thorium (Th) at element number 90, you begin to fill up the 5f sublevel and continue to fill up the 5f sublevel until you finish the actinide series at lawrencium (Lr).
According to IUPAC recommondations, the number of groups in the long form of the periodic table is :-- a)7
- b)8
- c)16
- d)18
Correct answer is option 'D'. Can you explain this answer?
According to IUPAC recommondations, the number of groups in the long form of the periodic table is :-
a)
7
b)
8
c)
16
d)
18
|
Krishna Iyer answered |
The correct option is D.
In chemistry, a group (also known as a family) is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table; the f-block columns (between groups 3 and 4) are not numbered.
In chemistry, a group (also known as a family) is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table; the f-block columns (between groups 3 and 4) are not numbered.
Nitrogen and phosphorus belong to the group 15 of the periodic table. Which of these will be more electronegative?- a)Phosphorus
- b)Both are equally electronegative
- c)Nitrogen
- d)None of these
Correct answer is option 'C'. Can you explain this answer?
Nitrogen and phosphorus belong to the group 15 of the periodic table. Which of these will be more electronegative?
a)
Phosphorus
b)
Both are equally electronegative
c)
Nitrogen
d)
None of these
|
Arun Yadav answered |
Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the Periodic Table. Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the Periodic Table. Write the electronic configuration of these two elements.
Which of the following elements of noble gases participate in chemical reaction?- a)Kr, Rn
- b)He, Kr
- c)Rn, He
- d)He, Ne
Correct answer is option 'A'. Can you explain this answer?
Which of the following elements of noble gases participate in chemical reaction?
a)
Kr, Rn
b)
He, Kr
c)
Rn, He
d)
He, Ne
|
|
Amit Kumar answered |
At high temperature and high pressure Krypton and Xenon forms some compounds like Xenon, Tetrafluride, xenon Oxyfluride.
The atomic number of an element is 16 predict the nature of the element- a)Non metallic
- b)Semi metallic
- c)Metallic
- d)None of these
Correct answer is option 'A'. Can you explain this answer?
The atomic number of an element is 16 predict the nature of the element
a)
Non metallic
b)
Semi metallic
c)
Metallic
d)
None of these
|
|
Sasmita Rout answered |
The atomic number of an element is 16 and it's configuration is 2,8,6. It's velency is 2. This element is known as Sulfur. It is non metallic because as we go from left to right in a periodic table the metallic character decreases while non metallic character increases.
Which element was discovered after Mendeleev gave the periodic table?- a)Gallium
- b)tantalum
- c)Aluminium
- d)manganese
Correct answer is option 'A'. Can you explain this answer?
Which element was discovered after Mendeleev gave the periodic table?
a)
Gallium
b)
tantalum
c)
Aluminium
d)
manganese
|
Sanvi Kapoor answered |
The element gallium was discovered four year's after the publication of Mendeleev's table, and it's properties matched up remarkably well with ek aluminum, fitting into the table exactly where he had predicted.
How many elements did Mendeleev classify?- a)63.0
- b)92.0
- c)61.0
- d)60.0
Correct answer is option 'A'. Can you explain this answer?
How many elements did Mendeleev classify?
a)
63.0
b)
92.0
c)
61.0
d)
60.0
|
|
Neha Joshi answered |
The correct answer is A as Mendeleev classify 63 elements in his periodic table.
The second ionization energy is greater than the first because- a)Second electron is heavy hence it needs more energy
- b)increased force of attraction between the nucleus and the valence electrons
- c)of decreased force of attraction between the nucleus and the valence electrons
- d)None of these
Correct answer is option 'B'. Can you explain this answer?
The second ionization energy is greater than the first because
a)
Second electron is heavy hence it needs more energy
b)
increased force of attraction between the nucleus and the valence electrons
c)
of decreased force of attraction between the nucleus and the valence electrons
d)
None of these
|
|
Madhu Sulaniya answered |
Since it is more difficult to remove ion from a positively charged ion then from an neutral atom.
Statement A : Electron affinity of fluorine is more than that of chlorine.
Statement B : Carbon monoxide is an acidic oxide.- a)Statement B is true, A is false
- b)Neither statement nor statement B is true
- c)Both the Statement A and B are true
- d)Statement A is true, B is false
Correct answer is option 'B'. Can you explain this answer?
Statement A : Electron affinity of fluorine is more than that of chlorine.
Statement B : Carbon monoxide is an acidic oxide.
Statement B : Carbon monoxide is an acidic oxide.
a)
Statement B is true, A is false
b)
Neither statement nor statement B is true
c)
Both the Statement A and B are true
d)
Statement A is true, B is false
|
|
Arun Sharma answered |
Electron affinity of chlorine is more than fluorine. Carbon monoxide do not show basic and acidic properties when they react with water. Therefore, it is neutral oxide.
Give the symbol for the most reactive non-metal of group 17- a)F
- b)Cl
- c)Br
- d)I
Correct answer is option 'A'. Can you explain this answer?
Give the symbol for the most reactive non-metal of group 17
a)
F
b)
Cl
c)
Br
d)
I
|
|
Sandeep Kumar answered |
Because "F" is the most electronegative of all of the elements of the periodic table.
Due to strong electronegativity and small size it has strong tendency to accept electron from other atoms or ions.
It oxidises all other substances.
This is the reason all the best.
Due to strong electronegativity and small size it has strong tendency to accept electron from other atoms or ions.
It oxidises all other substances.
This is the reason all the best.
Metallic character ____________ down a group- a)decreases
- b)remains the same in the group
- c)Increases
- d)None of these
Correct answer is option 'C'. Can you explain this answer?
Metallic character ____________ down a group
a)
decreases
b)
remains the same in the group
c)
Increases
d)
None of these
|
|
Dhruvi Shah answered |
Metallic character increases as you move down an element group in the periodic table. This is because electrons become easier to lose as the atomic radius increases, where there is less attraction between the nucleus and the valence electrons because of the increased distance between them.
Atomic number of the element which is surrounded by elements with atomic numbers 17, 34, 36 and 53 in the modern periodic table is- a)18
- b)35
- c)37
- d)52
Correct answer is option 'B'. Can you explain this answer?
Atomic number of the element which is surrounded by elements with atomic numbers 17, 34, 36 and 53 in the modern periodic table is
a)
18
b)
35
c)
37
d)
52
|
|
Ashwin Saha answered |
The atomic number of an element represents the number of protons in the nucleus of an atom of that element. In the modern periodic table, elements are arranged in order of increasing atomic number. Based on the information given, we can determine the atomic number of the element surrounded by elements with atomic numbers 17, 34, 36, and 53.
Identify the elements:
- The atomic number 17 corresponds to chlorine (Cl).
- The atomic number 34 corresponds to selenium (Se).
- The atomic number 36 corresponds to krypton (Kr).
- The atomic number 53 corresponds to iodine (I).
Determine the missing element:
To find the missing element, we need to look for an element that fits between atomic numbers 34 and 36. The atomic number 35 corresponds to the element bromine (Br). Therefore, bromine is the element surrounded by elements with atomic numbers 17, 34, 36, and 53.
The correct answer is option 'B' (35).
Identify the elements:
- The atomic number 17 corresponds to chlorine (Cl).
- The atomic number 34 corresponds to selenium (Se).
- The atomic number 36 corresponds to krypton (Kr).
- The atomic number 53 corresponds to iodine (I).
Determine the missing element:
To find the missing element, we need to look for an element that fits between atomic numbers 34 and 36. The atomic number 35 corresponds to the element bromine (Br). Therefore, bromine is the element surrounded by elements with atomic numbers 17, 34, 36, and 53.
The correct answer is option 'B' (35).
What type of oxide would Eka-aluminium form?- a)EO3
- b)E2O3
- c)E3O2
- d)EO
Correct answer is option 'B'. Can you explain this answer?
What type of oxide would Eka-aluminium form?
a)
EO3
b)
E2O3
c)
E3O2
d)
EO
|
Ashwini dubey answered |
Understanding Eka-Aluminium and Its Oxide Form
Eka-aluminium, known as Gallium (Ga), is a chemical element that belongs to the group of metals in the periodic table. It is important to understand how it reacts and what kind of oxides it forms.
Oxide Formation in Gallium
Gallium typically forms oxides in specific ratios, and the most common oxide it produces is Ga2O3.
Reason for the Answer (E2O3)
- Valency of Gallium:
- Gallium has a valency of +3, which means it can lose three electrons to form compounds.
- Combining with Oxygen:
- Oxygen typically has a valency of -2. To balance the charges, two Gallium atoms (each with a +3 charge) will combine with three oxygen atoms (each with a -2 charge).
- Chemical Formula Derivation:
- The ratio of Gallium to Oxygen in the oxide is thus 2:3, leading to the formula Ga2O3, which corresponds to option E2O3.
Other Options Explained
- EO3: This would imply a different valency not applicable to Gallium.
- E3O2: This would suggest a higher ratio of Gallium, which is not stable.
- EO: Represents a 1:1 ratio, which is also incorrect for Gallium.
Conclusion
Given the chemical properties and valency of Gallium, the oxide it forms is best represented by the formula E2O3, confirming option 'B' as the correct answer.
Eka-aluminium, known as Gallium (Ga), is a chemical element that belongs to the group of metals in the periodic table. It is important to understand how it reacts and what kind of oxides it forms.
Oxide Formation in Gallium
Gallium typically forms oxides in specific ratios, and the most common oxide it produces is Ga2O3.
Reason for the Answer (E2O3)
- Valency of Gallium:
- Gallium has a valency of +3, which means it can lose three electrons to form compounds.
- Combining with Oxygen:
- Oxygen typically has a valency of -2. To balance the charges, two Gallium atoms (each with a +3 charge) will combine with three oxygen atoms (each with a -2 charge).
- Chemical Formula Derivation:
- The ratio of Gallium to Oxygen in the oxide is thus 2:3, leading to the formula Ga2O3, which corresponds to option E2O3.
Other Options Explained
- EO3: This would imply a different valency not applicable to Gallium.
- E3O2: This would suggest a higher ratio of Gallium, which is not stable.
- EO: Represents a 1:1 ratio, which is also incorrect for Gallium.
Conclusion
Given the chemical properties and valency of Gallium, the oxide it forms is best represented by the formula E2O3, confirming option 'B' as the correct answer.
X and Y are two elements having similar properties which obey Newland’s Law of Octaves. The minimum and maximum number of elements in between X and Y, respectively are- a)6 and 13
- b)6 and 8
- c)7 and 15
- d)8 and 14
Correct answer is option 'B'. Can you explain this answer?
X and Y are two elements having similar properties which obey Newland’s Law of Octaves. The minimum and maximum number of elements in between X and Y, respectively are
a)
6 and 13
b)
6 and 8
c)
7 and 15
d)
8 and 14
|
Priyanka Kapoor answered |
X and Y are two elements having similar properties which obey Newlands’s Law of Octaves. The minimum and maximum number of elements in between X and Y respectively are 6 and 8.
Which of the following is not the limitation of Mendeleev’s periodic table?- a)He left gaps for yet to be discovered elements
- b)There was no place for isotopes in the periodic table
- c)There was no place for noble gases
- d)None of these
Correct answer is option 'A'. Can you explain this answer?
Which of the following is not the limitation of Mendeleev’s periodic table?
a)
He left gaps for yet to be discovered elements
b)
There was no place for isotopes in the periodic table
c)
There was no place for noble gases
d)
None of these
|
Anirudh Mukherjee answered |
To identify which statement is not the limitation of Mendeleev's periodic table, the merits and limitations of Mendeleev's periodic table must be identified.
Accordingly, the merits and limitation of Mendeleev's periodic table are as follows:
Merits of Mendeleev's periodic table:
Mendeleev's periodic table had the structural arrangement of elements as groups and periods.
He left spaces or gaps for yet-to-be-discovered elements and named them with succeeding elements prefixed with 'Eka'.
His periodic table also had positions for Nobel gas before their identification.
It corrected the incorrect atomic masses of many elements.
Limitations of Mendeleev's periodic table:
The assignment of a fixed position to element hydrogen was not possible.
His periodic table didn't have any position for isotopes of elements.
The atomic mass of elements was not increasing in order.
Whereas the statement given in option (a) is not the limitation, as it is one of the merits of Mendeleev's periodic table.
Elements having same valence electrons are placed in same group but there is an exception with-- a)Xe
- b)Ne
- c)Ar
- d)He
Correct answer is option 'D'. Can you explain this answer?
Elements having same valence electrons are placed in same group but there is an exception with-
a)
Xe
b)
Ne
c)
Ar
d)
He
|
|
Anshika Sarkar answered |
All the elements of group 18 have 8 valence electrons each in their atoms, except helium which has Only 2 valence electrons in its atom as it's duplet is complete.
Statement A : energy is always released when a neutral atoms gain an electron, Statement B Tellurium and polonium are semi metals- a)Statement B is true A is false
- b)Neither statement A nor statement B is true
- c)Statement A is true, B is false
- d)Both the statement A and B are true
Correct answer is option 'A'. Can you explain this answer?
Statement A : energy is always released when a neutral atoms gain an electron, Statement B Tellurium and polonium are semi metals
a)
Statement B is true A is false
b)
Neither statement A nor statement B is true
c)
Statement A is true, B is false
d)
Both the statement A and B are true
|
|
Krishna Iyer answered |
Energy is always released when a neutral atom gains an electron. This process is called electron affinity. It is reverse of ionization energy. Semimetals are also known as metalloids. Tellurium and polonium are one of the semi metals.
Which one has the bigger size?- a)K
- b)Na
- c)Cl
- d)F
Correct answer is option 'A'. Can you explain this answer?
Which one has the bigger size?
a)
K
b)
Na
c)
Cl
d)
F
|
|
Krishna Iyer answered |
The potassium atom has an extra electron shell compared to the sodium atom, which means it's valence electrons are further from the nucleus, giving potassium a larger atomic radius.
Three elements B, Si and Ge are- a)metals
- b)non-metals
- c)metalloids
- d)metal, non-metal and metalloid, respectively
Correct answer is option 'C'. Can you explain this answer?
Three elements B, Si and Ge are
a)
metals
b)
non-metals
c)
metalloids
d)
metal, non-metal and metalloid, respectively
|
|
Pranita mehta answered |
**Explanation:**
The elements B (Boron), Si (Silicon), and Ge (Germanium) are all located in Group 14 of the periodic table.
**1. Metalloids:**
Metalloids are elements that have properties of both metals and non-metals. They are located along the zigzag line on the periodic table, separating the metals from the non-metals.
**Boron (B):**
- Boron is a metalloid element.
- It is a non-metallic element that is typically brittle in its pure form.
- Boron is a poor conductor of electricity but can act as a semiconductor at high temperatures.
- It has properties of both metals and non-metals, making it a metalloid.
**Silicon (Si):**
- Silicon is a metalloid element.
- It is the second most abundant element in the Earth's crust and is widely used in the technology industry.
- Silicon has a shiny, metallic appearance but is a poor conductor of electricity at room temperature.
- It is used extensively in the production of computer chips and other electronic devices.
- Like boron, silicon has properties of both metals and non-metals, classifying it as a metalloid.
**Germanium (Ge):**
- Germanium is also a metalloid element.
- It has a similar shiny, metallic appearance to silicon.
- Germanium is a semiconductor and has useful electrical properties.
- It is used in transistors, solar cells, and other electronic applications.
- Similar to boron and silicon, germanium exhibits properties of both metals and non-metals, making it a metalloid.
Therefore, the correct answer is option **C) metalloids**, as all three elements B, Si, and Ge are metalloids.
The elements B (Boron), Si (Silicon), and Ge (Germanium) are all located in Group 14 of the periodic table.
**1. Metalloids:**
Metalloids are elements that have properties of both metals and non-metals. They are located along the zigzag line on the periodic table, separating the metals from the non-metals.
**Boron (B):**
- Boron is a metalloid element.
- It is a non-metallic element that is typically brittle in its pure form.
- Boron is a poor conductor of electricity but can act as a semiconductor at high temperatures.
- It has properties of both metals and non-metals, making it a metalloid.
**Silicon (Si):**
- Silicon is a metalloid element.
- It is the second most abundant element in the Earth's crust and is widely used in the technology industry.
- Silicon has a shiny, metallic appearance but is a poor conductor of electricity at room temperature.
- It is used extensively in the production of computer chips and other electronic devices.
- Like boron, silicon has properties of both metals and non-metals, classifying it as a metalloid.
**Germanium (Ge):**
- Germanium is also a metalloid element.
- It has a similar shiny, metallic appearance to silicon.
- Germanium is a semiconductor and has useful electrical properties.
- It is used in transistors, solar cells, and other electronic applications.
- Similar to boron and silicon, germanium exhibits properties of both metals and non-metals, making it a metalloid.
Therefore, the correct answer is option **C) metalloids**, as all three elements B, Si, and Ge are metalloids.
An element with atomic no 3 combines with another elements with atomic number 17, What would be the formulae of the compound?- a)NaCl
- b)LiCl
- c)Lif
- d)BeCl2
Correct answer is option 'B'. Can you explain this answer?
An element with atomic no 3 combines with another elements with atomic number 17, What would be the formulae of the compound?
a)
NaCl
b)
LiCl
c)
Lif
d)
BeCl2
|
|
Abhishek Phogat answered |
3 = lithium
17 = chlorine
Hence compound - licl...
17 = chlorine
Hence compound - licl...
Which pair of atomic numbers represents elements in the same group?- a)6, 12
- b)11, 19
- c)4, 16
- d)8, 17
Correct answer is option 'B'. Can you explain this answer?
Which pair of atomic numbers represents elements in the same group?
a)
6, 12
b)
11, 19
c)
4, 16
d)
8, 17
|
|
Ritu Saxena answered |
The difference between atomic numbers is 8.
Which set of elements is listed in order of increasing ionization energy?- a)Sb < As < S < P < Cl
- b)Cl < Sb < P < As < S
- c)As < Cl < P < S < Sb
- d)Sb < As < Cl < S < P
Correct answer is option 'A'. Can you explain this answer?
Which set of elements is listed in order of increasing ionization energy?
a)
Sb < As < S < P < Cl
b)
Cl < Sb < P < As < S
c)
As < Cl < P < S < Sb
d)
Sb < As < Cl < S < P
|
|
Gargi Pillai answered |
As atomic number increases along a period, ionization energy increases and in a group it decreases. For S and P, theoretically ionization energy of S should be greater than P but due to the stability of half filled electronic configuration, ionization energy of P is greater than S.
What is the defining characteristic of noble gases?- a) They have a full outer electron shell
- b) They are highly reactive
- c) They are metals
- d) They have low boiling points
Correct answer is option 'A'. Can you explain this answer?
What is the defining characteristic of noble gases?
a)
They have a full outer electron shell
b)
They are highly reactive
c)
They are metals
d)
They have low boiling points
|
Arizona Academy answered |
Noble gases, located in Group 18, are known for having a full outer electron shell, which makes them mostly inert and non-reactive under standard conditions. This stability is the reason why they do not easily form compounds.
What is the significance of the Law of Octaves proposed by Newlands?- a) It identifies noble gases.
- b) It arranges elements by atomic number.
- c) It classifies elements into triads.
- d) It suggests elements are similar every eighth element when arranged by atomic mass.
Correct answer is option 'D'. Can you explain this answer?
What is the significance of the Law of Octaves proposed by Newlands?
a)
It identifies noble gases.
b)
It arranges elements by atomic number.
c)
It classifies elements into triads.
d)
It suggests elements are similar every eighth element when arranged by atomic mass.
|
|
Arizona Academy answered |
Newlands' Law of Octaves states that when elements are arranged in order of increasing atomic mass, every eighth element exhibits similar properties. This concept was an important early step in the development of the periodic table.
What characteristic differentiates metals from non-metals?- a) Metals generally lose electrons to form positive ions.
- b) Metals tend to gain electrons to form negative ions.
- c) Metals are typically gases at room temperature.
- d) Metals have higher ionization energies.
Correct answer is option 'A'. Can you explain this answer?
What characteristic differentiates metals from non-metals?
a)
Metals generally lose electrons to form positive ions.
b)
Metals tend to gain electrons to form negative ions.
c)
Metals are typically gases at room temperature.
d)
Metals have higher ionization energies.
|
|
Arizona Academy answered |
Metals are characterized by their tendency to lose electrons and form positive ions, which contributes to their metallic character. This property is essential in many chemical reactions and helps define their reactivity.
Elements A, B and C Constitute a Dobereiner’s triad. If the atomic mass of element A is 7 and that of element C is 39, then what is the atomic mass of element B?- a)23
- b)46
- c)22
- d)32
Correct answer is option 'A'. Can you explain this answer?
Elements A, B and C Constitute a Dobereiner’s triad. If the atomic mass of element A is 7 and that of element C is 39, then what is the atomic mass of element B?
a)
23
b)
46
c)
22
d)
32
|
|
Priyanka Kapoor answered |
A, B and C are the elements of a Dobereiner's triad. If the atomic masses of A and C are 7 and 39 respectively, then according to Dobereiner's triad law, the atomic mass of B is the average of the atomic masses of A and C.
So, the average of the atomic masses of A and C
Therefore, the atomic mass of B is 23.
So, the average of the atomic masses of A and C
Therefore, the atomic mass of B is 23.
Which of the following elements will form an acidic oxide?- a)An element with atomic number 3
- b)An element with atomic number 7
- c)An element with atomic number 12
- d)A element with atomic number 19
Correct answer is option 'B'. Can you explain this answer?
Which of the following elements will form an acidic oxide?
a)
An element with atomic number 3
b)
An element with atomic number 7
c)
An element with atomic number 12
d)
A element with atomic number 19
|
|
Ritu Saxena answered |
Metallic character increases down a group and decreases along a period. Thus, metallic character increases in the order: Be, Mg, Ca.
An element which is an essential constituent of all organic compounds belongs to- a)Group 1
- b)Group 2
- c)Group 14
- d)Group 15
Correct answer is option 'C'. Can you explain this answer?
An element which is an essential constituent of all organic compounds belongs to
a)
Group 1
b)
Group 2
c)
Group 14
d)
Group 15
|
|
Ritu Saxena answered |
The essential constituent of all organic matter is carbon which belongs to group 17.
Which of the following elements is most likely to have a high ionization energy?- a) Potassium
- b) Sodium
- c) Neon
- d) Lithium
Correct answer is option 'C'. Can you explain this answer?
Which of the following elements is most likely to have a high ionization energy?
a)
Potassium
b)
Sodium
c)
Neon
d)
Lithium
|
|
Arizona Academy answered |
Neon is most likely to have a high ionization energy because it is a noble gas with a full outer electron shell, making it stable and less likely to lose electrons compared to alkali metals like lithium and sodium.
Which period is considered the longest in the periodic table?- a) Second period
- b) Sixth period
- c) Seventh period
- d) First period
Correct answer is option 'B'. Can you explain this answer?
Which period is considered the longest in the periodic table?
a)
Second period
b)
Sixth period
c)
Seventh period
d)
First period
|
|
Arizona Academy answered |
The sixth period is the longest period in the periodic table, containing 32 elements. This is due to the filling of the f-orbitals, which allows for a greater number of electrons and elements in this row.
In the modern periodic table which are the metals among the first 10 elements?- a)Be, C
- b)Li, B
- c)Li, Be
- d)B, Be
Correct answer is option 'C'. Can you explain this answer?
In the modern periodic table which are the metals among the first 10 elements?
a)
Be, C
b)
Li, B
c)
Li, Be
d)
B, Be
|
|
Trisha sengupta answered |
Understanding the Modern Periodic Table
The modern periodic table organizes elements based on their atomic numbers and properties. The first ten elements include hydrogen (H), helium (He), lithium (Li), beryllium (Be), boron (B), carbon (C), nitrogen (N), oxygen (O), fluorine (F), and neon (Ne).
Identifying Metals Among the First 10 Elements
In the context of the first ten elements, we need to identify which of them are classified as metals.
Metals in the First 10 Elements:
- Lithium (Li):
- It's an alkali metal, known for its reactivity and is found in Group 1 of the periodic table.
- Beryllium (Be):
- This is an alkaline earth metal located in Group 2, recognized for its strength and light weight.
Other Elements and Their Classification:
- Hydrogen (H):
- Although it is located at the top of the periodic table, it is a non-metal.
- Helium (He):
- This is a noble gas and is also classified as a non-metal.
- Boron (B):
- This element is a metalloid, not a metal.
- Carbon (C):
- Carbon is a non-metal.
- Nitrogen (N):
- This is a non-metal.
- Oxygen (O):
- Another non-metal.
- Fluorine (F):
- This is also a non-metal.
- Neon (Ne):
- A noble gas, classified as a non-metal.
Conclusion
Thus, the only metals among the first ten elements are lithium (Li) and beryllium (Be), making option 'C' the correct answer.
The modern periodic table organizes elements based on their atomic numbers and properties. The first ten elements include hydrogen (H), helium (He), lithium (Li), beryllium (Be), boron (B), carbon (C), nitrogen (N), oxygen (O), fluorine (F), and neon (Ne).
Identifying Metals Among the First 10 Elements
In the context of the first ten elements, we need to identify which of them are classified as metals.
Metals in the First 10 Elements:
- Lithium (Li):
- It's an alkali metal, known for its reactivity and is found in Group 1 of the periodic table.
- Beryllium (Be):
- This is an alkaline earth metal located in Group 2, recognized for its strength and light weight.
Other Elements and Their Classification:
- Hydrogen (H):
- Although it is located at the top of the periodic table, it is a non-metal.
- Helium (He):
- This is a noble gas and is also classified as a non-metal.
- Boron (B):
- This element is a metalloid, not a metal.
- Carbon (C):
- Carbon is a non-metal.
- Nitrogen (N):
- This is a non-metal.
- Oxygen (O):
- Another non-metal.
- Fluorine (F):
- This is also a non-metal.
- Neon (Ne):
- A noble gas, classified as a non-metal.
Conclusion
Thus, the only metals among the first ten elements are lithium (Li) and beryllium (Be), making option 'C' the correct answer.
What is the trend of atomic size as you move down a group in the periodic table?- a) Atomic size remains constant
- b) Atomic size decreases
- c) Atomic size varies unpredictably
- d) Atomic size increases
Correct answer is option 'D'. Can you explain this answer?
What is the trend of atomic size as you move down a group in the periodic table?
a)
Atomic size remains constant
b)
Atomic size decreases
c)
Atomic size varies unpredictably
d)
Atomic size increases
|
Lakesway Classes answered |
As you move down a group, the atomic size increases. This occurs due to the addition of electron shells, which increases the distance between the outermost electrons and the nucleus, resulting in a larger atomic radius.
The term "reactive metals" primarily refers to which groups in the periodic table?- a) Noble gases
- b) Transition metals
- c) Groups 1 and 2
- d) Groups 13 to 17
Correct answer is option 'C'. Can you explain this answer?
The term "reactive metals" primarily refers to which groups in the periodic table?
a)
Noble gases
b)
Transition metals
c)
Groups 1 and 2
d)
Groups 13 to 17
|
|
Arizona Academy answered |
Reactive metals are primarily found in Groups 1 and 2 of the periodic table. These metals, such as lithium and sodium, readily lose electrons to form positive ions, making them highly reactive, especially with water and acids.
Which of the following elements is considered a non-metal?- a) Iron
- b) Oxygen
- c) Copper
- d) Sodium
Correct answer is option 'B'. Can you explain this answer?
Which of the following elements is considered a non-metal?
a)
Iron
b)
Oxygen
c)
Copper
d)
Sodium
|
|
Arizona Academy answered |
Oxygen is classified as a non-metal. Non-metals are typically found in the upper right corner of the periodic table and are characterized by their ability to gain electrons during chemical reactions.
How many periods are present in the long form of the periodic table?- a) 10
- b) 12
- c) 7
- d) 5
Correct answer is option 'C'. Can you explain this answer?
How many periods are present in the long form of the periodic table?
a)
10
b)
12
c)
7
d)
5
|
|
Arizona Academy answered |
The long form of the periodic table consists of seven periods. Each period represents a row of elements, and these periods vary in the number of elements they contain, reflecting the increasing atomic numbers.
What is the number of valance electrons in the last element of 3rd period?- a)7.0
- b)5.0
- c)8.0
- d)3.0
Correct answer is option 'C'. Can you explain this answer?
What is the number of valance electrons in the last element of 3rd period?
a)
7.0
b)
5.0
c)
8.0
d)
3.0
|
|
Isha Tiwari answered |
Understanding Valence Electrons in the 3rd Period
Valence electrons are the outermost electrons of an atom and play a crucial role in chemical bonding and reactivity. In the periodic table, elements are arranged in periods and groups based on their electron configuration.
Elements in the 3rd Period
- The 3rd period consists of the following elements:
- Sodium (Na)
- Magnesium (Mg)
- Aluminum (Al)
- Silicon (Si)
- Phosphorus (P)
- Sulfur (S)
- Chlorine (Cl)
- Argon (Ar)
Last Element of the 3rd Period
- The last element of the 3rd period is Argon (Ar).
- Argon is a noble gas, which means it has a complete outer electron shell.
Valence Electrons of Argon
- Argon has the electron configuration of [Ne] 3s² 3p⁶.
- This configuration indicates that Argon has a total of 8 valence electrons (2 in the 3s subshell and 6 in the 3p subshell).
Conclusion
- The correct answer to the question regarding the number of valence electrons in the last element of the 3rd period (Argon) is option 'C' (8.0).
- This completeness makes noble gases like Argon generally unreactive, as they do not tend to gain or lose electrons easily.
Understanding the valence electrons helps in predicting the behavior of elements in chemical reactions, particularly in the context of bonding and stability.
Valence electrons are the outermost electrons of an atom and play a crucial role in chemical bonding and reactivity. In the periodic table, elements are arranged in periods and groups based on their electron configuration.
Elements in the 3rd Period
- The 3rd period consists of the following elements:
- Sodium (Na)
- Magnesium (Mg)
- Aluminum (Al)
- Silicon (Si)
- Phosphorus (P)
- Sulfur (S)
- Chlorine (Cl)
- Argon (Ar)
Last Element of the 3rd Period
- The last element of the 3rd period is Argon (Ar).
- Argon is a noble gas, which means it has a complete outer electron shell.
Valence Electrons of Argon
- Argon has the electron configuration of [Ne] 3s² 3p⁶.
- This configuration indicates that Argon has a total of 8 valence electrons (2 in the 3s subshell and 6 in the 3p subshell).
Conclusion
- The correct answer to the question regarding the number of valence electrons in the last element of the 3rd period (Argon) is option 'C' (8.0).
- This completeness makes noble gases like Argon generally unreactive, as they do not tend to gain or lose electrons easily.
Understanding the valence electrons helps in predicting the behavior of elements in chemical reactions, particularly in the context of bonding and stability.
According to Mendeleev's Periodic Law, elements are arranged based on which of the following criteria?- a) Similar chemical properties
- b) Increasing atomic mass
- c) Increasing atomic number
- d) Mass number
Correct answer is option 'C'. Can you explain this answer?
According to Mendeleev's Periodic Law, elements are arranged based on which of the following criteria?
a)
Similar chemical properties
b)
Increasing atomic mass
c)
Increasing atomic number
d)
Mass number
|
|
Arizona Academy answered |
Mendeleev's Periodic Law states that elements are arranged in order of increasing atomic mass, which allowed him to predict the properties of undiscovered elements. However, the modern periodic table is organized by increasing atomic number.
The elements A, B, C, D and E have atomic number 9, 11, 17, 12 and 13 respectively. Which pair of elements belong to the same group?- a)A and C
- b)A and D
- c)A and E
- d)B and D
Correct answer is option 'A'. Can you explain this answer?
The elements A, B, C, D and E have atomic number 9, 11, 17, 12 and 13 respectively. Which pair of elements belong to the same group?
a)
A and C
b)
A and D
c)
A and E
d)
B and D
|
|
Ritu Saxena answered |
Let us take a look at the electronic configurations of the given elements,
A: (2, 7)
B: (2, 8, 1)
C: (2, 8, 7)
D: (2, 8, 2)
E: (2, 8, 3)
We can see that elements A and C both have 7 valence electrons. Thus, both the elements belong to the same group.
So, the correct option is A.
A: (2, 7)
B: (2, 8, 1)
C: (2, 8, 7)
D: (2, 8, 2)
E: (2, 8, 3)
We can see that elements A and C both have 7 valence electrons. Thus, both the elements belong to the same group.
So, the correct option is A.
Which one of the following elements exhibit maximum number of valence electrons?- a)Na
- b)P
- c)Al
- d)Si
Correct answer is option 'B'. Can you explain this answer?
Which one of the following elements exhibit maximum number of valence electrons?
a)
Na
b)
P
c)
Al
d)
Si
|
|
Vivek Bansal answered |
- Electronic configuration of Na, Al, Si and P are 2, 8 1, 2, 8, 3, 2, 8, 4, and 2, 8, 5 respectively.
- Valence electrons in Na, Al, Si and P are 1,3,4 and 5.
- Hence phosphorus has maximum number of valence electrons.
The element with atomic number 14 is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?- a)Metal
- b)Non-metal
- c)Metalloid
- d)Left hand side element
Correct answer is option 'C'. Can you explain this answer?
The element with atomic number 14 is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?
a)
Metal
b)
Non-metal
c)
Metalloid
d)
Left hand side element
|
|
Ritu Saxena answered |
Since the element with atomic number 14 i.e., Si forms an acidic oxide and a covalent halide, it must be metalloid.
Which of the following does not increase while moving down the group of the periodic table?- a)Atomic radius
- b)Valence
- c)Metallic character
- d)Number of shells in on element
Correct answer is option 'B'. Can you explain this answer?
Which of the following does not increase while moving down the group of the periodic table?
a)
Atomic radius
b)
Valence
c)
Metallic character
d)
Number of shells in on element
|
|
Ritu Saxena answered |
In a group valency of all elements is fixed because of having the same outer shell electronic configuration while all the remaining three properties increase down the group.
Which of the given element A, B, C, D and E with atomic numbers 2, 3, 7, 10 and 30, respectively belong to the same period?- a)A, B, C
- b)B, C, D
- c)A, D, E
- d)B, D, E
Correct answer is option 'B'. Can you explain this answer?
Which of the given element A, B, C, D and E with atomic numbers 2, 3, 7, 10 and 30, respectively belong to the same period?
a)
A, B, C
b)
B, C, D
c)
A, D, E
d)
B, D, E
|
|
Vivek Bansal answered |
2nd period contains elements with atomic numbers 3 (Li), 7 (N) 10 (Ne).
Where would you locate the element with electronic configuration 2, 8 in the modern period table?- a)Group 2
- b)Group 8
- c)Group 10
- d)Group 18
Correct answer is option 'D'. Can you explain this answer?
Where would you locate the element with electronic configuration 2, 8 in the modern period table?
a)
Group 2
b)
Group 8
c)
Group 10
d)
Group 18
|
|
Vivek Bansal answered |
Elements with electronic configuration (2, 8) is an inert gas i.e., neon and hence belongs to group 18.
What does the atomic number of an element represent?- a) The number of protons in the nucleus
- b) The number of electrons in a neutral atom
- c) The number of neutrons in the nucleus
- d) The total mass of the element
Correct answer is option 'A'. Can you explain this answer?
What does the atomic number of an element represent?
a)
The number of protons in the nucleus
b)
The number of electrons in a neutral atom
c)
The number of neutrons in the nucleus
d)
The total mass of the element
|
|
Arizona Academy answered |
The atomic number is defined as the number of protons in the nucleus of an atom. This value is unique for each element and determines its identity. For example, hydrogen has an atomic number of 1, meaning it has one proton.
The correct sequences of atomic radii is- a)Na > Mg > Al > Si
- b)Si >Al > Mg > Na
- c)Al > Si > Na > Mg
- d)Si > Al > Na > Mg
Correct answer is option 'A'. Can you explain this answer?
The correct sequences of atomic radii is
a)
Na > Mg > Al > Si
b)
Si >Al > Mg > Na
c)
Al > Si > Na > Mg
d)
Si > Al > Na > Mg
|
|
Vivek Bansal answered |
Within a period, atomic radii decrease from left to right.
Which of the following gives the correct increasing order of the atomic radii of O, F and N?- a)F, O, N
- b)O, F, N
- c)N, F, O
- d)O, N, F
Correct answer is option 'A'. Can you explain this answer?
Which of the following gives the correct increasing order of the atomic radii of O, F and N?
a)
F, O, N
b)
O, F, N
c)
N, F, O
d)
O, N, F
|
|
Radha Iyer answered |
Atomic radius decreases across a period because nuclear charges increase across a period. When the charge increases, the electrons are pulled towards the nucleus with greater force decreasing the size of the atomic radius. Hence Fluorine has the least radius as its atomic number is larger than oxygen and nitrogen. The same case is with oxygen, it has more number of positive charges than nitrogen. Hence nitrogen has the largest size than oxygen and then fluorine.
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