Question

(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?

Answer 1

(a) All the elements in the same column as boron have the same number of valence electrons $3$. Hence, they all have valency equal to $3$.

(b) All elements belong to same column as fluorine, are non-metals and are highly electronegative in character. All of them have valence electrons equal to seven, and thus can accept one electron to complete their octet.