Question

1. analyze: how does the atomic radius change across a period of the periodic table? (activity b continued on next page)

Explanation:

As we move across a period (from left to right) in the periodic table, the number of protons in the nucleus increases. This leads to a greater positive charge in the nucleus. At the same time, the electrons are added to the same principal energy level. The increased nuclear charge pulls the electrons closer to the nucleus.

Answer:

The atomic radius decreases across a period of the periodic table.