Which of the following elements has the smallest atomic radius?

The correct answer is Chlorine.

• Among Bromine, Chlorine, Sodium and Calcium; the atomic radius of Chlorine is the smallest.

Key Points

• The atomic radius is the distance from the nucleus of an atom to the outermost electrons.
• Atomic radii vary in a predictable way across the periodic table.
• 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.