121. $$N{a^ + },M{g^{2 + }},A{l^{3 + }}$$ and $$S{i^{4 + }}$$ are isoelectronic. The order of their ionic size is
A
$$N{a^ + } > M{g^{2 + }} < A{l^{3 + }} < S{i^{4 + }}$$
B
$$N{a^ + } < M{g^{2 + }} > A{l^{3 + }} > S{i^{4 + }}$$
C
$$N{a^ + } > M{g^{2 + }} > A{l^{3 + }} > S{i^{4 + }}$$
D
$$N{a^ + } < M{g^{2 + }} > A{l^{3 + }} < S{i^{4 + }}$$
Answer :
$$N{a^ + } > M{g^{2 + }} > A{l^{3 + }} > S{i^{4 + }}$$
122.
Consider the following four elements, which are represented according to long form of periodic table.
Here $$W, Y$$ and $$Z$$ are left, up and right elements with respect to the element $$'X'$$ and $$'X'$$ belongs to 16th group and 3rd period. Then according to given information the incorrect statement regarding given elements is:
A
Maximum electronegativity : $$Y$$
B
Maximum catenation property : $$X$$
C
Maximum electron affinity : $$Z$$
D
$$Y$$ exhibits variable covalency
Answer :
$$Y$$ exhibits variable covalency
123. Which of the following electronic configurations is of transition elements?
A
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}4{s^2}$$
B
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^{10}}4{s^2}4{p^1}$$
C
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^{10}}4{s^2}4{p^6}$$
D
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^2}4{s^2}$$
Answer :
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^2}4{s^2}$$
124.
Electronic configurations of four elements $$A, B, C$$ and $$D$$ are given below :
$$\eqalign{
& \left( A \right)1{s^2}2{s^2}2{p^6} \cr
& \left( B \right)1{s^2}2{s^2}2{p^4} \cr
& \left( C \right)1{s^2}2{s^2}2{p^6}3{s^1} \cr
& \left( D \right)1{s^2}2{s^2}2{p^5} \cr} $$
Which of the following is the correct order of increasing tendency to gain electron?
A
$$A < C < B < D$$
B
$$A < B < C < D$$
C
$$D < B < C < A$$
D
$$D < A < B < C$$
Answer :
$$A < C < B < D$$
125.
Few values are given in the table in the direction from left to right and top to bottom. Predict the property which could be depicted in the table.
A
Atomic number
B
Ionisation enthalpy
C
Atomic radius
D
Electron gain enthalpy
Answer :
Atomic radius
126. Which of the following order is wrong ?
A
$$N{H_3} < P{H_3} < As{H_3} - {\text{Acidic}}$$
B
$$Li < Be < B < C - I{E_1}$$
C
$$A{l_2}{O_3} < MgO < N{a_2}O < {K_2}O - {\text{Basic}}$$
D
$$L{i^ + } < N{a^ + } < {K^ + } < C{s^ + } - {\text{Ionic radius}}$$
Answer :
$$Li < Be < B < C - I{E_1}$$
127. Which of the following is arranged in order of increasing metallic character?
A
$$P < Si < Na < Be < Mg$$
B
$$Be < Mg < P < Na < Si$$
C
$$Si < Be > Mg < Na < P$$
D
$$P < Si < Be < Mg < Na$$
Answer :
$$P < Si < Be < Mg < Na$$
128. The electronic configuration of an element is . The atomic number and the group number of the element $$'X'$$ which is just below the above element in the periodic table are respectively
A
23 and 5
B
23 and 15
C
33 and 15
D
33 and 5
Answer :
33 and 15
129. The set of three elements having successive atomic numbers and having the ionization energies of $$2372, 520$$ and $$890\,kJ$$ per $$mol$$ is
A
$$H,He,Li$$
B
$$He,Li,Be$$
C
$$Li,Be,B$$
D
$$B,C,N$$
Answer :
$$He,Li,Be$$
130. Which one of the following statements is incorrect in relation to ionisation enthalpy ?
A
Ionisation enthalpy increases for each successive electron.
B
The greatest increase in ionisation enthalpy is experienced on removal of electron from core noble gas configuration.
C
End of valence electrons is marked by a big jump in ionisation enthalpy.
D
Removal of electron from orbitals bearing lower $$n$$ value is easier than from orbital having higher $$n$$ value.
Answer :
Removal of electron from orbitals bearing lower $$n$$ value is easier than from orbital having higher $$n$$ value.