Question

Becl2 is covalent while Mgcl2 is ionic?​

Answer 1

Answer:

BeCl2 is covalent while Mgcl2 is ionic as Be and Mg belongs to same group of valency 2 because magnesium is highly reactive in nature and react with chlorine to form ionic or electrostatic bond while BeCl2 is not more reactive to form ionic bond and that's why it share electron and form covalent bond

Answer 2

Answer:

Beryllium is 2nd period. It has a very small atomic size and high ionisation enthalpy. Hence it does not form ion but form covalent $\sf{BeCl_2}$. Magnesium is in 3rd period.

Magnesium due to its lower ionisation enthalpy and bigger atomic size loses its valence electrons easily forming $\sf{Mg^{2+}}$ ions. Thus, $\sf{BeCl_2}$, is covalent whereas $\sf{MgCl_2}$ is ionic.