Question

use radius is the smallest

Answer 1

Answer:

Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest.

Answer 2

Answer:

As you go across a period, electrons are added to the same energy level. At the same time, protons are being added to the nucleus. The concentration of more protons in the nucleus creates a higher effective nuclear charge. In other words, there is a stronger force of attraction pulling the electrons closer to the nucleus resulting in a smaller atomic radius.Also, Anions are larger than their respective atoms as electron-electron repulsion forces them to spread further apart.

Hence, Cl has the smallest radius.