Question

Few elements are matched with their successive ionization energies. Identify the elements.

Element	$I{E}_1$(kJ/mol)	$I{E}_2$(kJ/mol)
$X$	2372	5251
$Y$	520	7297
$Z$	900	1758

• A. $\left(X\right)$ A noble gas $\left(Y\right)$ Alkali metal $\left(Z\right)$ Alkaline earth metal
• B. $\left(X\right)$ Alkali metal $\left(Y\right)$ A noble gas $\left(Z\right)$ Alkaline earth metal
• C. $\left(X\right)$ Alkaline earth metal $\left(Y\right)$ Alkali metal $\left(Z\right)$ A noble gas
• D. $\left(X\right)$ Alkali metal $\left(Y\right)$ Alkaline earth metal $\left(Z\right)$ A noble gas

Answer 1

Answer: (A)

$\left(X\right)$ A noble gas $\left(Y\right)$ Alkali metal $\left(Z\right)$ Alkaline earth metal

Noble gases ($n{s}^{2}n{p}^6$) have fully filled orbitals and thus have highest $I{E}_1$ and high $I{E}_2$

Alkali metals ($n{s}^1$) have one valence electron in s-orbital and thus have low $I{E}_1$ but very high $I{E}_2$.

Alkaline earth metals ($n{s}^2$) have fully filled s-orbital and thus have higher $I{E}_1$ but lower $I{E}_2$ than alkali metals.

Hence $X=$ noble gas, $Y=$ Alkali metals, $Z=$ Alkaline earth metals