Question

In a group, the atomic size:

Answer 1

Trends in atomic size:

• As you go down from top to bottom, the number of energy levels or electron shells increases so the atomic radius of the elements increases.
• In general, for the main group elements of the periodic table, the atomic radius increases down the group, from top to bottom.
• Atomic radius decreases across a period, from left to right, of the periodic table.

Hence, the atomic size increases from top to bottom in a group because new shells are being added as we go down the group.