Question

From the given set of species, point out the species from each set having the least atomic radius respectively.

(a) $O^{2-},F^{-},N{a}^{+}$

(b) $Ni,Cu,Zn$

(c) $Li,Be,Mg$

(d) $He,L{i}^{+},H^{-}$

• A. $O^{2-},Cu,Li,H^{-}$
• B. $N{a}^{+},Ni,Be,L{i}^{+}$
• C. $F^{-},Zn,Mg,He$
• D. $N{a}^{+},Cu,Be,He$

Answer 1

The correct option is B $N{a}^{+},Ni,Be,L{i}^{+}$

The atomic radius is lower due to the high effective nuclear charge (due to poor shielding by inner electrons).
In group (a), $N{a}^{+}$ has the least atomic radius.
In group (b), $Ni$ has the least atomic radius.
In group (c), $Be$ has the least atomic radius.
In group (d), $L{i}^{+}$ has the least atomic radius.

Hence option $B$ is correct.