Question

What is the general trend in atomic size within a group across a period?

A) Decreases within a group, increases across a period
B) Increases within a group, decreases across a period
C) Increases both within a group and across a period
D) Decreases both within a group and across a period

Answer 1

The general trend in atomic size within a group across a period is that the atomic size generally decreases within a group and increases across a period.

Step-by-step explanation:

The general trend in atomic size within a group across a period is that the atomic size generally decreases within a group and increases across a period.

Within a group, as you move down the column, the atomic size increases. This is because the valence electrons add in the higher shell in each consecutive member of a group, resulting in a larger atomic radius. On the other hand, across a period, as you move from left to right, the atomic size decreases. This is because the valence electrons are in the same shell while more protons add to the nucleus, increasing the pull on the valence electrons and causing a smaller atomic radius.