Question

An element has $2$ electrons in its fourth shell. State:
(d) position in the periodic table

Answer 1

The number of shells present in an atom determines its period and the number of valence electrons determines the group.
Since the element has $2$ electrons in its fourth shell which defines that it has $4$ shells and $2$ valence electrons.
Therefore, the element is placed in period $4$ and group $2$.