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All questions of Periodic Classification of Element for Class 10 Exam
In the Modern Periodic Table, if an element with atomic number ‘X’ is an inert gas, then an element with atomic number (X-1) will be placed in:- a)Group 16
- b)Group 17
- c)Group 15
- d)Group 18
Correct answer is option 'B'. Can you explain this answer?
In the Modern Periodic Table, if an element with atomic number ‘X’ is an inert gas, then an element with atomic number (X-1) will be placed in:
a)
Group 16
b)
Group 17
c)
Group 15
d)
Group 18
|
Arun Sharma answered |
All the Noble gases are placed in the group 18 and all elements are placed in the order of increasing atomic number. Therefore, the elements of atomic number before the Noble gas is placed in the before group of the period of Nobel gas which is group 17.
How many elements were known when Mendeleev started his work on his periodic table?- a)63
- b)55
- c)69
- d)45
Correct answer is option 'A'. Can you explain this answer?
How many elements were known when Mendeleev started his work on his periodic table?
a)
63
b)
55
c)
69
d)
45
|
Nisha Choudhury answered |
There were 63 known elements in 1860 when Mendeleev published his Periodic Table. CIENTISTS HAD IDENTIFIED over 63 elements by Mendeleev's time.
The Law of Octaves was applicable only upto element ________.- a)Sodium
- b)Calcium
- c)Zinc
- d)Copper
Correct answer is option 'B'. Can you explain this answer?
The Law of Octaves was applicable only upto element ________.
a)
Sodium
b)
Calcium
c)
Zinc
d)
Copper
|
Vikram Kapoor answered |
The major limitations of Newlands' law of octaves were :
It was applicable to only lighter elements having atomic masses upto 40 u, i.e., upto calcium. After calcium, the first and the eighth element did not have similar properties. For example chromium (Cr) and yttrium (Y) are the first and the eighth element placed in the same column but they have entirely different properties.
It was applicable to only lighter elements having atomic masses upto 40 u, i.e., upto calcium. After calcium, the first and the eighth element did not have similar properties. For example chromium (Cr) and yttrium (Y) are the first and the eighth element placed in the same column but they have entirely different properties.
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
The elements of group 16 are called- a)Chalcogens
- b)Halogens
- c)Pnicogens
- d)Noble gases
Correct answer is option 'A'. Can you explain this answer?
The elements of group 16 are called
a)
Chalcogens
b)
Halogens
c)
Pnicogens
d)
Noble gases
|
|
Vikram Kapoor answered |
The group 16 elements of modern periodic table consist of 5 elements oxygen, sulphur, selenium, tellurium and polonium. The elements in this group are also known as the chalcogens.
Which one is more metallic element ?- a)Na
- b)Mg
- c)Al
- d)Si
Correct answer is option 'A'. Can you explain this answer?
Which one is more metallic element ?
a)
Na
b)
Mg
c)
Al
d)
Si
|
|
Diya Sharma answered |
Because it more fastly or quickly loss it's electron.
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).
The most distinctive property of the noble gases is that they are:- a)Unreactive
- b)Radioactive
- c)Metalloid
- d)Metallic
Correct answer is option 'A'. Can you explain this answer?
The most distinctive property of the noble gases is that they are:
a)
Unreactive
b)
Radioactive
c)
Metalloid
d)
Metallic
|
|
Nisha Choudhury answered |
Because, their valency is zero.
ie., their outer shell (orbital) of electrons is "full", significantly limiting their ability to form chemical bonds. (A chemical bond is essentially a region lying between two atoms with a maximum probability for electrons to be present. The electrons in the 'bond' are kinda shared between both the atoms, and they keep the repelling nuclei of the two atoms together by being electrostatic-ally attracted to both. In quantum chemistry (using Schroedinger's equation), it is seen that, the state with the 'orbitals' being filled have a 'lower free energy' than states with unfilled orbitals. Atoms without filled orbitals react so as to achieve this 'lower energy' stable state. This is explained by the valence-bond theory/molecular orbital theory models).
All the noble gases have all their orbitals full, and hence their 'unfilled states in the orbitals available for bonding' (valency) is zero. This significantly reduces their ability to bond with other atoms. This is why, noble gases are very unreactive.
Which of the following has the maximum non-metallic character ?- a)F
- b)Cl
- c)Br
- d)I
Correct answer is option 'A'. Can you explain this answer?
Which of the following has the maximum non-metallic character ?
a)
F
b)
Cl
c)
Br
d)
I
|
|
Ananya Das answered |
Non metallic character decreases as we move down the group. In a group, the size of an element increases because there is an addition of new shell and electron is added in that shell. Hence, fluorine has the most non metallic character.
Arrange the following elements in the order of their increasing non-metallic character
Li, O, C, Be, F- a)F < O < C < Be < Li
- b)Li < Be < C < O < F
- c)F < Be < C < O < Li
- d)F < O < Be < C < Li
Correct answer is option 'B'. Can you explain this answer?
Arrange the following elements in the order of their increasing non-metallic character
Li, O, C, Be, F
Li, O, C, Be, F
a)
F < O < C < Be < Li
b)
Li < Be < C < O < F
c)
F < Be < C < O < Li
d)
F < O < Be < C < Li
|
|
Gaurav Kumar answered |
This is the correct order of increasing non-metallic character.
Which of the following is correct order of atomic size - a)Cl < F < Br < I
- b)F < Cl < Br < I
- c)I < Br < Cl < F
- d)Br < I < Cl < F
Correct answer is option 'B'. Can you explain this answer?
Which of the following is correct order of atomic size
a)
Cl < F < Br < I
b)
F < Cl < Br < I
c)
I < Br < Cl < F
d)
Br < I < Cl < F
|
|
Amit Kumar answered |
Trend of atomic size is :-
In period it decreases due to large Electronegativity . In group it increases due to low Electronegativity. According to this order, option ( b) is correct.
In period it decreases due to large Electronegativity . In group it increases due to low Electronegativity. According to this order, option ( b) is correct.
How many triads could Dobereiner identify from the elements known at that time?a) 3b) 5c) 4d) 2Correct answer is option 'A'. Can you explain this answer?
|
Pooja Shah answered |
In 1817 a German chemist Johann Wolfgang Döbereiner arranged the elements with similar properties into groups.
Some groups were identified having three elements each. So he called these groups ‘triads’. Only three triads could be identified from the elements discovered at that time.
MCQ (Multiple Choice Questions) or Practice Quiz with solutions of Chapter - "Periodic Classification of Elements" of Class 10 Science, the questions are available for practice Q. According to IUPAC recommendations, 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?
MCQ (Multiple Choice Questions) or Practice Quiz with solutions of Chapter - "Periodic Classification of Elements" of Class 10 Science, the questions are available for practice
Q. According to IUPAC recommendations, the number of groups in the long form of the periodic table is :-
a)
7
b)
8
c)
16
d)
18
|
Krishna Iyer answered |
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.
Which of the following triads is a Dobereiner’s Triad?- a)N, P, As
- b)S, O, H
- c)Na, Ra, Al
- d)Li, Na, K
Correct answer is option 'D'. Can you explain this answer?
Which of the following triads is a Dobereiner’s Triad?
a)
N, P, As
b)
S, O, H
c)
Na, Ra, Al
d)
Li, Na, K
|
|
Anjana Khatri answered |
DOBEREINER TRIADS RULE :
In 1817, Johann walfgang dobereiner. A German chemist, arranged the elements is group of three elements and in a manner that the atomic mass of middle element was roughly the average of the atomic masses of the other two elements of the triad.
Example:
In the triad of lithium, sodium and potassium. The atomic mass of lithium is 7 and the atomic mass of potassium is 39. The average of masses of lithium and potassium gives atomic mass of sodium 23.
Which of the following is the outermost shell for elements of period 2 ?- a)K shell
- b)L shell
- c)M shell
- d)N shell
Correct answer is option 'B'. Can you explain this answer?
Which of the following is the outermost shell for elements of period 2 ?
a)
K shell
b)
L shell
c)
M shell
d)
N shell
|
Naman das answered |
For the second period elements, L-shell is the outermost shell.
Which of the following gives the correct increasing order of the atomic radii of O, F and N ?- a)O, F, N
- b)N, F, O
- c)O, N, F
- d)F, O, N
Correct answer is option 'D'. Can you explain this answer?
Which of the following gives the correct increasing order of the atomic radii of O, F and N ?
a)
O, F, N
b)
N, F, O
c)
O, N, F
d)
F, O, N
|
|
Amit Sharma answered |
Moving from right to left the periodic table metallic character increases and if metallic character increase atomic size will also increase as a result atomic radii increase.
Lanthanides belong to which period?- a)4
- b)5
- c)6
- d)7
Correct answer is option 'C'. Can you explain this answer?
Lanthanides belong to which period?
a)
4
b)
5
c)
6
d)
7
|
|
Vikram Kapoor answered |
Lanthanides belong to 6th period.They start from atomic number 58 and ends in 71
X (atomic mass = 37), Y (atomic mass = 81), and Z are three members of Dobereiner’s triads. Atomic mass of Z=?- a)59
- b)125
- c)130
- d)None of the above
Correct answer is option 'B'. Can you explain this answer?
X (atomic mass = 37), Y (atomic mass = 81), and Z are three members of Dobereiner’s triads. Atomic mass of Z=?
a)
59
b)
125
c)
130
d)
None of the above
|
Trisha Vashisht answered |
Atomic mass of Y = (Atomic mass of X + Atomic mass of Z)/2
81 = (37 + Z) /2
162 -37 = Z
Z = 125
Element X forms a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be:- a)Si
- b)Al
- c)Na
- d)Mg
Correct answer is 'D'. Can you explain this answer?
Element X forms a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be:
a)
Si
b)
Al
c)
Na
d)
Mg
|
|
Ananya Das answered |
X = Mg
Because Mg has valency 2 and valency in a group remains the same.
When Mg combines with chlorine it forms MgCl2.
Which one of the following elements exhibit maximum number of valence electrons ?- a)Na
- b)Al
- c)Si
- d)P
Correct answer is option 'D'. Can you explain this answer?
Which one of the following elements exhibit maximum number of valence electrons ?
a)
Na
b)
Al
c)
Si
d)
P
|
|
Pooja Shah answered |
The greater the valency of the element, the greater is its unreactivity. Also, the valency in a period increases from the left to the middle, then again decreases from middle to the right. So we can say that the unreactive elements are located in the center of the period. Since phosphorus and Silicon are located at the center, they have the highest number of Valence electrons, and hence are the most unreactive in the period.
Which of the given elements A, B, C, D and E with atomic number 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 elements A, B, C, D and E with atomic number 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
|
|
Amit Kumar answered |
At no. of elements a,b,c,d,e are 2,3,7,10,30. Elements b , c , d belongs to the same period because the no. of valence shells are all 2. Elements B (Li), C (N) and D (Ne) belong to the same group.
In the third period of the periodic table the element having smallest size is
- a)Na
- b)Ar
- c)Cl
- d)Si
Correct answer is option 'C'. Can you explain this answer?
In the third period of the periodic table the element having smallest size is
a)
Na
b)
Ar
c)
Cl
d)
Si
|
|
Pooja Shah answered |
The correct answer is option 3: Cl (chlorine). Among the elements listed, chlorine (Cl) has the smallest size in the third period of the periodic table. Sodium (Na) and silicon (Si) are in the third period as well but have larger atomic sizes. Argon (Ar) is a noble gas and is not in the same period as the other elements mentioned.
Electropositive character of elements in a period ___________ from left to right- a)remains the same
- b)Increases
- c)decreases
- d)All of these
Correct answer is option 'C'. Can you explain this answer?
Electropositive character of elements in a period ___________ from left to right
a)
remains the same
b)
Increases
c)
decreases
d)
All of these
|
Rahul Kapoor answered |
Electropositive character in a period from left to right
Metallic character decreases across a period from left to right. On the other hand non-metallic character increases with increase in atomic number across a period.
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.
Which of the following has largest atomic size ?- a)Be
- b)C
- c)O
- d)F
Correct answer is option 'A'. Can you explain this answer?
Which of the following has largest atomic size ?
a)
Be
b)
C
c)
O
d)
F
|
|
Neha Patel answered |
Has the largest atomic number just after the largest noble gas, is a metal. It fits the criteria. Francium has a larger covalent and "Vander Waals" radius than Cesium, but Francium is an extremely unstable element and hence right now the prestige goes to Cesium.
With an increase in temperature by 10k ,the rate of reaction becomes double. How many times the rate of reaction will be, if the temperature is increased from 303 k to 353 k ?- a)4
- b)8
- c)16
- d)32
Correct answer is option 'D'. Can you explain this answer?
With an increase in temperature by 10k ,the rate of reaction becomes double. How many times the rate of reaction will be, if the temperature is increased from 303 k to 353 k ?
a)
4
b)
8
c)
16
d)
32
|
|
N I K H I L answered |
5 Times Increase Hua Hai Bhaii Temperature
2^5 Times Means = 32
2^5 Times Means = 32
Which of the following has lowest number of electrons in the valence shell ?
- a)O
- b)C
- c)N
- d)B
Correct answer is option 'D'. Can you explain this answer?
Which of the following has lowest number of electrons in the valence shell ?
a)
O
b)
C
c)
N
d)
B
|
C K Academy answered |
As we can see, the no. of electrons in the valence shell of oxygen (8) is => 6
In valence shell of carbon (6) => 4
In valence shell of Nitrogen (7) => 5
In valence shell of boron (5) => 3
Therefore, boron has the lowest electron in the valence shell.
In valence shell of carbon (6) => 4
In valence shell of Nitrogen (7) => 5
In valence shell of boron (5) => 3
Therefore, boron has the lowest electron in the valence shell.
An element has an atomic number of 15 with which of the following elements will it show similar chemical properties. - a)Be (4)
- b)Ne (10)
- c)N(7)
- d)O (8)
Correct answer is option 'C'. Can you explain this answer?
An element has an atomic number of 15 with which of the following elements will it show similar chemical properties.
a)
Be (4)
b)
Ne (10)
c)
N(7)
d)
O (8)
|
|
Krishna Iyer answered |
The valence electrons of the atomic number 15 has 5 electrons in its outermost shell . Nitrogen also has 5 electrons in it's outer shell. It also belongs to 15 th group and has same chemical properties, others have 2,8 and 6 in their outermost shell.
In order to fit elements into his table, Newlands adjusted two elements in the same slot, but also put some unlike elements in the same slot.
- a)True
- b)False
Correct answer is option 'A'. Can you explain this answer?
In order to fit elements into his table, Newlands adjusted two elements in the same slot, but also put some unlike elements in the same slot.
a)
True
b)
False
|
Meera Rana answered |
For example, cobalt and nickel were in the same slot and these were placed in the same column as fluorine, chlorine and bromine which have very different properties than these elements. Iron,which resembles cobalt and nickel in properties,had been placed far away from these elements.
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.
Which among the following elements has the largest atomic radii ?- a)Na
- b)Mg
- c)K
- d)Ca
Correct answer is option 'C'. Can you explain this answer?
Which among the following elements has the largest atomic radii ?
a)
Na
b)
Mg
c)
K
d)
Ca
|
|
Raghav Bansal answered |
Atomic radii increases as you move left to right or down the columns of the periodic table. Within a period of elements, each new electron is added to the same shell. When an electron is added, a new proton is also added to the nucleus, which gives the nucleus a stronger positive charge and a greater nuclear attraction. So as more electrons are added, the total radius of the atom increases. And so out of all the options, potassium (K) has the largest atomic radii.
Dobereiner’s triad arranged the elements with similar properties into:- a)Periods
- b)Groups
- c)Both period and group
- d)None of these
Correct answer is option 'B'. Can you explain this answer?
Dobereiner’s triad arranged the elements with similar properties into:
a)
Periods
b)
Groups
c)
Both period and group
d)
None of these
|
|
Rohan Kapoor answered |
For example, Dobereiner arranged groups of three elements with similar properties into 'triads'. Newlands and Mendeleev arranged the elements in order of increasing relative atomic mass.
Newlands classification of elements did not include _______ .- a)Metalloids
- b)Metals
- c)Noble gases
- d)Non-metals
Correct answer is option 'C'. Can you explain this answer?
Newlands classification of elements did not include _______ .
a)
Metalloids
b)
Metals
c)
Noble gases
d)
Non-metals
|
|
Arun Yadav answered |
Noble gases were not found as and could not be a part of Newland's law of octaves, as:
1. These gases are inert and do not react with any other element.
2. These gases are found in nature in very small proportions.
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.
As we move from left to right in a period in modern periodic table, Atomic sizes of the elements generally- a) increaseq
- b)decrease
- c) remain same
- d)approach zero
Correct answer is option 'B'. Can you explain this answer?
As we move from left to right in a period in modern periodic table, Atomic sizes of the elements generally
a)
increaseq
b)
decrease
c)
remain same
d)
approach zero
|
|
Rahul Kapoor answered |
In a period, more electrons are added to the same shell as we go from left to right because the atomic number increases. This also increases the attraction between electrons and protons and that's why atomic size decreases. Increasing nuclear charge pulls the electrons closer to the nucleus.
Mendeleev’s classification was based on _______ .- a)Increasing atomic mass
- b)Decreasing atomic number
- c)Increasing atomic number
- d)Decreasing atomic mass
Correct answer is option 'A'. Can you explain this answer?
Mendeleev’s classification was based on _______ .
a)
Increasing atomic mass
b)
Decreasing atomic number
c)
Increasing atomic number
d)
Decreasing atomic mass
|
|
Krishna Iyer answered |
Mendeleev's Periodic Law states that the properties of elements are the periodic function of their relative atomic masses. Mendeleev arranged all 63 elements; which were discovered till his time; in the order of their increasing relative atomic masses in a tabular form. It is known as Mendeleev's Periodic Table.
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.
The least metallic element of group 1 is :-- a)Lithium
- b)Sodium
- c)Potassium
- d)Caesium
Correct answer is option 'A'. Can you explain this answer?
The least metallic element of group 1 is :-
a)
Lithium
b)
Sodium
c)
Potassium
d)
Caesium
|
|
Rahul Kapoor answered |
The group 1 elements in the periodic table are known as the alkali metals. They include lithium, sodium and potassium, which all react vigorously with air and water.
Which group of periodic table does Ge belongs to ?
- a)12 group
- b)11 group
- c)13 group
- d)14 group
Correct answer is option 'D'. Can you explain this answer?
Which group of periodic table does Ge belongs to ?
a)
12 group
b)
11 group
c)
13 group
d)
14 group
|
|
Anjana Khatri answered |
The carbon group is a periodic table group consisting of carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl). In modern IUPAC notation, it is called Group 14.
Where would you locate the element with electronic configuration 2, 8 in the Modern Periodic Table ?- a)Group 8
- b)Group 2
- c)Group 18
- d)Group 10
Correct answer is option 'C'. Can you explain this answer?
Where would you locate the element with electronic configuration 2, 8 in the Modern Periodic Table ?
a)
Group 8
b)
Group 2
c)
Group 18
d)
Group 10
|
Anirudh trivedi answered |
Group 18, the element is Neon. It belongs to group 18.
In Newlands law of octaves elements are arranged in order of- a)increasing atomic mass
- b)decreasing atomic number
- c)increasing atomic number
- d)decreasing atomic mass
Correct answer is option 'A'. Can you explain this answer?
In Newlands law of octaves elements are arranged in order of
a)
increasing atomic mass
b)
decreasing atomic number
c)
increasing atomic number
d)
decreasing atomic mass
|
|
Rohan Kapoor answered |
In 1864, Newlands arranged the known 56 elements in the order of increasing atomic masses.
He observed that the properties of every eighth element are similar to the properties of the first element.
Based on this observation, he proposed the Law of Octaves for the classification of elements.
Law of Octaves: When the elements are arranged in the increasing order of their atomic masses, the properties of every eighth element are similar to the first.
Element X forms a chloride with the formula XCl2, Which is a solid with a high metingpoint, X would most likely be in the same group of the periodic table as :-- a)Na
- b)Mg
- c)Al
- d)Si
Correct answer is option 'B'. Can you explain this answer?
Element X forms a chloride with the formula XCl2, Which is a solid with a high metingpoint, X would most likely be in the same group of the periodic table as :-
a)
Na
b)
Mg
c)
Al
d)
Si
|
Utkarsh Joshi answered |
The correct answer is B as elements of group Na form XCl halide.
Elements of group Mg form XCl2 halide.
Elements of group Al form XCl3 halide.
Elements of group Si form XCl4 halide.
As an element, X forms a chloride with the formula XCl2 which is solid with a high melting point. X would most likely be in the same group of Mg.
Elements of group Mg form XCl2 halide.
Elements of group Al form XCl3 halide.
Elements of group Si form XCl4 halide.
As an element, X forms a chloride with the formula XCl2 which is solid with a high melting point. X would most likely be in the same group of Mg.
The law of triads is not applicable to:- a)Os, Ir, Pt
- b)Ca, Sr, Ba
- c)Fe, Co, Ni
- d)Ru, Rh, Pt
Correct answer is option 'C,D'. Can you explain this answer?
The law of triads is not applicable to:
a)
Os, Ir, Pt
b)
Ca, Sr, Ba
c)
Fe, Co, Ni
d)
Ru, Rh, Pt
|
|
Kiran Mehta answered |
The law of triads does not apply to Ru, Rh, Pt.
Modern periodic law was proposed by:
- a)D.I. mendeleev
- b)Dobereincer
- c)H.G.I moselly
- d)Newlands
Correct answer is option 'C'. Can you explain this answer?
Modern periodic law was proposed by:
a)
D.I. mendeleev
b)
Dobereincer
c)
H.G.I moselly
d)
Newlands
|
|
Aditya Kumar answered |
Modern periodic law was proposed by Henry Moseley in 1913. According to the modern periodic law, the properties of the elements and their compounds are a periodic function of their atomic numbers..
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.
What is the nature of an element having atomic number 20?- a)metalloid
- b)metallic
- c)non metallic
- d)semi metallic
Correct answer is option 'B'. Can you explain this answer?
What is the nature of an element having atomic number 20?
a)
metalloid
b)
metallic
c)
non metallic
d)
semi metallic
|
|
Amit Kumar answered |
The element with atomic number 20 is Calcium (Ca) and it has metallic character as it loses two valence electrons easily to complete it's octet.
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