How does atomic radius change as you move down the periodic table?

As you move down the periodic table, the atomic radius increases. This increase is primarily due to the addition of electron shells. Each time you move down a group, an additional energy level is added, which means that the electrons are positioned further from the nucleus. Although the positive charge from the nucleus does increase because of the addition of protons, the effect of increased distance and electron shielding outweighs the increased nuclear charge. Consequently, the outermost electrons are less tightly held by the nucleus, resulting in an overall larger atomic radius.

The idea that atomic radius increases towards the bottom left aligns with this trend, since as you go towards the bottom of a group, you are adding more shells of electrons, leading to an increase in size. This increase continues as you move left in the periodic table, where elements generally have fewer protons and the effective nuclear charge on the outermost electrons is less pronounced than in the transition to the right, where electrons are added to the same shell with increasing nuclear charge.