Column-I (Type of element)	Column-II (Outer electronic configuration)
A) Inert gas elements	i)  ${\text{ns}}^{1-2}{\text{ and ns}}^2{\text{ np}}^1{\text{ to ns}}^2{\text{ np}}^5$
B) Representative elements	ii) ${\text{1s}}^2{\text{ and ns}}^2{\text{ np}}^6$
C) Transition elements	iii) ${\text{(n-2)f}}^{1-14}{\text{ (n-1)d}}^{0-1}{\text{ns}}^2$
D) Inner-transition elements	iv) ${\text{(n-1)d}}^{1-10}{\text{ ns}}^{1 or 2}$