When’s I would like to say that it may be B because
The alkali metals are first column, alkali earth 2nd, halogens 2nd to last, and noble gases last. Hope it helps!
<span>D.) Oxygen would acquire a stable arrangement of electrons by bonding with two atoms of "Magnesium"
[ As Mg has 2 extra electrons & their size are quite similar ]
Hope this helps!</span>
67.45 is the answer I think
