From the given set of species, point out the species from each set having least atomic radius:-

$\left(\mathrm{i}\right) {\mathrm{O}}^{-2},{\mathrm{F}}^{-},{\mathrm{Na}}^{+}$

$\left(\mathrm{ii}\right) \mathrm{Ni},\mathrm{Cu},\mathrm{Zn}$

$\left(\mathrm{iii}\right) \mathrm{Li}, \mathrm{Be}, \mathrm{Mg}$

$\left(\mathrm{iv}\right) \mathrm{He},{\mathrm{Li}}^{+},{\mathrm{H}}^{-}$

$\mathrm{Be}$ and $\mathrm{Mg}$ have zero value of electron affinity, because:

In the following electronic configuration:

${\mathrm{ns}}^2\left(\mathrm{n}-1\right){\mathrm{d}}^{0-1}\left(\mathrm{n}-2\right){\mathrm{f}}^{1-14}$ If value of $\left(\mathrm{n}-1\right)=6$ the configuration will be of: