Which element among the alkaline earth metals primarily forms covalent compounds?

Discuss the trend of the following:
$(i)$ Thermal stability of carbonates of Group $-2$ elements.
$(ii)$ The solubility and the nature of oxides of Group $-2$ elements.

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$ :
Assertion $(A)$ : $BeCl_2$ and $MgCl_2$ produce characteristic flame.
Reason $(R)$ : The excitation energy is high in $BeCl_2$ and $MgCl_2$.
In the light of the above statements,choose the correct answer from the option given below :

$Be(OH)_2$ is insoluble in water while $Ba(OH)_2$ is highly soluble due to:

Statement $A$: Helium and Beryllium have the same outer electronic configuration of the type $ns^2$.
Reason $R$: Both are chemically inert.

The compounds of alkaline earth metals have the following magnetic nature: