Question

The atom having smallest atomic size (a) H (b) He (c) Li (d) Na​

Answer 1

Answer:

Helium(He)

Explanation:

This is due to trends in the periodic table, and the effective nuclear charge that holds the valence electrons close to the nucleus. Atomic radius decreases as you move across a period from left to right and decreases as you move up a group from bottom to top.