# Atomic radii and why does it decrease in a period [closed]

Why do atomic radii decreases as you move from left to right across a period

Atomic radius decreases across a period because electrons are being added to the same energy level and at the same time the nucleus is increasing in protons. The increase in nuclear charge $$Z_{eff}$$ attracts the electrons more strongly, (addition of one proton has a greater effect than addition of 1 electron) thus pulling electron closer to the nucleus and making atomic radius decrease.