Question

Why the size of oxygen is larger than fluroin atom?

Answer 1

Oxygen has eight electrons in its shells. Thus electrons in oxygen atom will be closer to nucleus than in the case of nitrogen. The same explanation applies for fluorine where the atom has nine electrons. When electrons are closer it means atomic radius is smaller.

Answer 2

Explanation:

Nuclear charge will hold the electrons closer but this force will be lesser when compared to oxygen and fluorine. Oxygen has eight electrons in its shells. The eight protons in oxygen atom's nucleus will exert more force than Fluorine's seven electrons. ... When electrons are closer it means atomic radius is smaller.