81.
First three ionisation energies $$\left( {{\text{in}}\,kJ/mol} \right)$$ of three representative elements are given below :
| Element | $$I{E_1}$$ | $$I{E_2}$$ | $$I{E_3}$$ |
| $$P$$ | 495.8 | 4562 | 6910 |
| $$Q$$ | 737.7 | 1451 | 7733 |
| $$R$$ | 577.5 | 1817 | 2745 |
Then incorrect option is :
A
$$Q :$$ Alkaline earth metal
B
$$P :$$ Alkali metals
C
$$R :$$ $$s$$ - block element
D
They belong to same period
Answer :
$$R :$$ $$s$$ - block element
82. Which one of the following ions will be smallest in size?
A
$$N{a^ + }$$
B
$$M{g^{2 + }}$$
C
$${F^ - }$$
D
$$O_2^ - $$
Answer :
$$M{g^{2 + }}$$
83.
In the given graph, a periodic property $$\left( R \right)$$ is plotted against atomic numbers $$\left( Z \right)$$ of the elements. Which property is shown in the graph and how it is correlated with reactivity of the elements?
A
Ionisation enthalpy in a group, reactivity decreases from $$a \to e.$$
B
Ionisation enthalpy in a group, reactivity increases from $$a \to e.$$
C
Atomic radius in a group, reactivity decreases from $$a \to e.$$
D
Metallic character in a group, reactivity increases from $$a \to e.$$
Answer :
Ionisation enthalpy in a group, reactivity increases from $$a \to e.$$
84. In which of the following arrangements, the sequence is not strictly according to the property written against it?
A
$$HF < HCl < HBr,HI:$$ increasing acid strength
B
$$N{H_3} < P{H_3} < As{H_3} < Sb{H_3}:$$ increasing basic strength
C
$$B < C < O < N:$$ increasing first ionization enthalpy
D
$$C{O_2} < Si{O_2} < Sn{O_2} < Pb{O_2}:$$ increasing oxidising power
Answer :
$$N{H_3} < P{H_3} < As{H_3} < Sb{H_3}:$$ increasing basic strength
85. Which one of the following ionic species has the greatest proton affinity to form stable compound ?
A
$$C{l^ - }$$
B
$${F^ - }$$
C
$${I^ - }$$
D
$$B{r^ - }$$
Answer :
$${F^ - }$$
86. Ionisation enthalpies of transition metals are
A
intermediate between those of $$s$$ - and $$p$$ - block elements
B
more than $$p$$ - block elements
C
highest in all the elements
D
lower than $$s$$ - block elements
Answer :
intermediate between those of $$s$$ - and $$p$$ - block elements
87. The element $$Z = 114$$ has been discovered recently. It will belong to which of the following family/group and electronic configuration?
A
Halogen family, $$\left[ {Rn} \right]5{f^{14}}\,6{d^{10}}\,7{s^2}\,7{p^5}$$
B
Carbon family, $$\left[ {Rn} \right]5{f^{14}}\,6{d^{10}}\,7{s^2}\,7{p^2}$$
C
Oxygen family, $$\left[ {Rn} \right]5{f^{14}}\,6{d^{10}}\,7{s^2}\,7{p^4}$$
D
Nitrogen family, $$\left[ {Rn} \right]5{f^{14}}\,6{d^{10}}\,7{s^2}\,7{p^6}$$
Answer :
Carbon family, $$\left[ {Rn} \right]5{f^{14}}\,6{d^{10}}\,7{s^2}\,7{p^2}$$
88. Which one of the following is the smallest in size?
A
$${N^{3 - }}$$
B
$${O^{2 - }}$$
C
$${F^ - }$$
D
$$N{a^ + }$$
Answer :
$$N{a^ + }$$
89. Identify the correct order of acidic strengths of $$C{O_2},CuO,CaO,{H_2}O$$
A
$$CaO < CuO < {H_2}O < C{O_2}$$
B
$${H_2}O < CuO < CaO,C{O_2}$$
C
$$CaO < {H_2}O < CuO < C{O_2}$$
D
$${H_2}O < C{O_2} < CaO < CuO$$
Answer :
$$CaO < CuO < {H_2}O < C{O_2}$$
90. Highest electron affinity is shown by
A
$${O^ - }$$
B
$${F^ - }$$
C
$$C{l_2}$$
D
$${F_2}$$
Answer :
$${O^ - }$$