Question

what is the similarity in the electronic configuration of the following set of atom be ,ca mg​

Answer 1

They all have outermost or valence electron as 2
Electronic configuration of be is 2, 2
Ca is 2,8,8,2
Mg is 2,8,2
So they have valence electron as 2
HOPE THIS HELP YOU

Answer 2

the valence shell has 2 electrons

these all belongs to 2nd group of modern periodic table

Be    2 \

Mg   2,8

Ca    2,8,8

hope it helps!!!! :):)