Question

State the factors which affect the atomic size of elements in a periodic table. In period 2 from left to right, state which element has the largest atomic size and which element has the smallest, giving reasons.

Answer 1

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 period This is because on moving across a period, number of shells remains the same but the nuclear charge increases by one at each step.