The atom having the number of electron shell as 4 and valence electrons as 2 belongs to
group 14 or IV A and period 4
When you look at the periodic table, each row is called a period. All of the elements in a period have the same number of electron shells. The periodic table also has a special name for its vertical columns. Each column is called a group. The elements in each group have the same number of valence electrons. The number of electron shells represents period and number of valence electrons represents the group.
Here the atom have number of electron shells as 4 and valence electrons as 3 thus it belongs to period 4 and group 2.