Classification of Elements and Periodicity in Properties MCQ Questions & Answers in Inorganic Chemistry | Chemistry
Learn Classification of Elements and Periodicity in Properties MCQ questions & answers in Inorganic Chemistry are available for students perparing for IIT-JEE, NEET, Engineering and Medical Enternace exam.
171.
Which of the following elements shown as pairs with their atomic numbers belong to the same period?
A
$$Z = 19\,\,{\text{and}}\,\,Z = 38$$
B
$$Z = 12\,\,{\text{and}}\,\,Z = 17$$
C
$$Z = 11\,\,{\text{and}}\,\,Z = 21$$
D
$$Z = 16\,\,{\text{and}}\,\,Z = 35$$
Answer :
$$Z = 12\,\,{\text{and}}\,\,Z = 17$$
$$\eqalign{
& Z = 12,1{s^2}2{s^2}2{p^6}3{s^2}\left( {n = 3} \right) \cr
& Z = 17,1{s^2}2{s^2}2{p^6}3{s^2}3{p^5}\left( {n = 3} \right) \cr} $$
172.
The first, second and third ionization enthalpies of an element are 737, 1450 and 7731 $$kJ\,mo{l^{ - 1}}$$ respectively. What will be the formulae of its oxide and chloride?
A
$${M_2}O,MCl$$
B
$$MO,MC{l_2}$$
C
$${M_2}{O_3},MC{l_3}$$
D
$$M{O_2},MC{l_4}$$
Answer :
$$MO,MC{l_2}$$
The element belongs to group 2, and so it forms $$MO$$ and $$MC{l_2}.$$
173.
If the ionization enthalpy and electron gain enthalpy of an element are $$275$$ and $$86\,kcal\,mo{l^{ - 1}}$$ respectively, then the electronegativity of the element on the Pauling scale is :
174.
Which of the following elements will have highest ionisation energy?
A
$$1{s^2}2{s^2}2{p^6}3{s^1}$$
B
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^3}$$
C
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^4}$$
D
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^1}$$
Answer :
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^3}$$
Half-filled orbitals have extra stability, hence they have high ionisation energy.
175.
The order of increasing sizes of atomic radii among the elements $$O, S, Se$$ and $$As$$ is :
A
$$As < S < O < Se$$
B
$$Se < S < As < O$$
C
$$O < S < As < Se$$
D
$$O < S < Se < As$$
Answer :
$$O < S < Se < As$$
On moving down in a group atomic radii increases due to successive addition of extra shell hence $$O < S < Se$$
Further $$As$$ is in group 15 having one less electron in its $$p$$ orbital hence have higher atomic radii than group 16 elements.
i.e., $$O < S < Se < As$$
176.
One would expect proton to have very large
A
charge
B
ionisation potential
C
hydration energy
D
radius
Answer :
hydration energy
Proton have very small size, so have large hydration energy. The degree of hydration depends upon the size of the cation. Smaller the size of a cation greater the hydration energy.
177.
Which property decreases from left to right across the periodic table and increases from top to bottom ?
(i) Atomic radius
(ii) Electronegativity
(iii) Ionisation energy
(iv) Metallic character
A
(i) only
B
(i), (ii) and (iii)
C
(i), (iii) and (iv)
D
(i) and (iv)
Answer :
(i) and (iv)
Atomic radius and metallic character decreases from left to right across the period and increases from top to bottom down the group.
178.
Which of the following is not a merit of Mendeleev's periodic table?
A
It helped in correcting the atomic masses of some of the elements.
B
He predicted the properties of some undiscovered elements and left gaps for them.
C
He framed the periodic table with vertical and horizontal columns and gave shape to it.
D
He gave separate places to isotopes in his periodic table.
Answer :
He gave separate places to isotopes in his periodic table.
Mendeleev could not give separate places to isotope in the periodic table which had different atomic weights.
179.
The order of screening effect of electrons of $$s, p, d$$ and $$f$$ orbitals of a given shell of an atom on its outer shell electrons is
A
$$s > p > d > f$$
B
$$f > d > p > s$$
C
$$p < d < s > f$$
D
$$f > p > s > d$$
Answer :
$$s > p > d > f$$
For the same shell, screening effect decreases in the order : $$s > p > d > f.$$
180.
Consider the following changes :
$$\eqalign{
& \left( {\text{i}} \right)M\left( s \right) \to M\left( g \right) \cr
& \left( {{\text{ii}}} \right)M\left( s \right) \to {M^{2 + }}\left( g \right) + 2{e^ - } \cr
& \left( {{\text{iii}}} \right)M\left( g \right) \to {M^ + }\left( g \right) + {e^ - } \cr
& \left( {{\text{iv}}} \right){M^ + }\left( g \right) \to {M^{2 + }}\left( g \right) + {e^ - } \cr
& \left( {\text{v}} \right)M\left( g \right) \to {M^{2 + }}\left( g \right) + 2{e^ - } \cr} $$
The second ionization energy of $$M$$ could be calculated from the energy values associated with :
A
(i) + (iii) + (iv)
B
(ii) - (i) + (iii)
C
(i) + (v)
D
(v) - (iii)
Answer :
(v) - (iii)
Second ionization energy is amount of energy required to take out an electron from the monopositive cation.