Epsom salt is a hydrate of which of the following?

Which of the following alkaline earth metals shows some properties similar to aluminium?

Thermal stability of $MCO_3$ is in order:

$Assertion$ $(A)$: Helium and beryllium have similar outer electronic configuration $ns^2$. $Reason$ $(R)$: Both are chemically inert.

Describe the importance of the following:
$(i)$ limestone
$(ii)$ cement
$(iii)$ plaster of Paris.

$BeCl_2$ reacts with $LiAlH_4$ to give ....