Factors affecting the atomic size are:
1. Number of shells: As number of shells increases, atomic size i.e. the distance of the outermost shell from the nucleus also increases.
2. Nuclear charge: As nuclear charge increases, atomic size decreases. This is because a greater nuclear charge means a greater attraction between the nucleus and the electrons in the outermost shell. Lithium(Li) has the largest Atomic size and Fluorine (F) has the smallest Atomic size in ** This is because on moving across a **, number of shells *** the same but the nuclear charge increases by one at each step.
