In case of isoelectronic species,the size of $F^{-}$,$Ne$,and $Na^{+}$ is affected by:

The size of isoelectronic species $F^{-},$ $Ne$ and $Na^{+}$ is affected by
$(a)$ Nuclear charge $(Z)$
$(b)$ Valence principal quantum number $(n)$
$(c)$ Electron-electron interaction in the outer orbitals
$(d)$ None of the factors because their size is the same.

Explain the measurement methods of atomic radius.

Given below are the pairs of group $13$ elements showing their relation in terms of atomic radius: $(B < Al)$, $(Al < Ga)$, $(Ga < In)$ and $(In < Tl)$. Identify the elements present in the incorrect pair and in that pair,find out the element $(X)$ that has a higher ionic radius $(M^{3+})$ than the other one. The atomic number of the element $(X)$ is:

From the given set of species,point out the species from each set having the least atomic radius.
$A. F^{-}, Na^{+}, Mg^{+2}$
$B. Ni, Cu, Zn$
$C. N^{-3}, Cs^{+}, H^{-}$
$D. Li, He, Be^{+2}$

In $K^{+} F^{-}$ ionic,the ionic radius of $F^{-}$ is more,while the atomic radius of $K^{+}$ is: