Question

Halides of alkaline earth metals are ionic except:

• A. $Be$
• B. $Mg$
• C. $Ca$
• D. $Ba$

Answer 1

The correct option is A $Be$

Option $\left(A\right)$ is correct.

Halides of alkaline earth metals are ionic except $Be$. The polarising power of beryllium is high and the polarisability of halides is also high so beryllium essentially pulls the donated electrons back so they are effectively shared.

Beryllium is a small atom and forms a +2 charge so it has a high charge density making it easier for it to pull the electrons away from the halide despite its high EN value.