Question

If first ionization enthalpies of element $X$ and $Y$ are $419\, kJ\, mol ^{-1}$ and $590\, kJ \, mol ^{-1}$, respectively and second ionization enthalpies of $X$ and $Y$ are $3069 \, kJ \, mol { }^{-1}$ and $1145\, kJ \, mol ^{-1}$, respectively. Then correct statement is :-

• A. $X$ is an alkali metal and $Y$ is an alkaline earth metal.
• B. $X$ is an alkaline earth metal and $Y$ is an alkali metal.
• C. Both $X$ and $Y$ are alkali metals.
• D. Both $X$ and $Y$ are alkaline earth metals.

Answer 1

Answer: (A)

$2^{\text {nd }}$ I.E. of alkali metals much higher than that of alkaline earth metal, due to noble gas configuration.