Question

1. explain the chemistry concept that causes the atomic radius to change across a period (left to right).

Explanation:

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

Answer:

The atomic radius decreases from left to right across a period due to the increase in nuclear charge (number of protons) which pulls the electrons closer to the nucleus while the electrons are in the same principal energy level.