Question

The $\left(I{E}_1\right)$ and the $\left(I{E}_2\right)$ in $kJmo{l}^{-1}$ of a few elements designated by Roman numerals are shown below:
$\begin{array}{ccc}& I& II\\ I{E}_1& 400& 589\\ I{E}_2& 2510& 1120\end{array}$
Elements $I$ and $II$ respectively are likely to be?

• A. Non-metal, alkali metal
• B. Alkali metal, alkaline earth metal
• C. Alkaline earth metal, non metal
• D. Alkaline earth metal, alkali metal

Answer 1

The correct option is B Alkali metal, alkaline earth metal

For $I$, the second ionization energy is 6 times that of the first ionization energy. This huge jump indicates that the atom attains a stable electronic configuration after the removal of the first electron. Hence, it must br an alkali metal.

For $II$, the first ionization energy is lower than the second ionization energy and there is no significant jump. So, it must be an alkaline earth metal.