As you move down Group 1 in the periodic table, how does the atomic radius of the elements change?

• A. The atomic radius decreases.
• B. The atomic radius increases.
• C. The atomic radius remains the same.
• D. The atomic radius first increases, then decreases.

Answer: (B)

Verified step by step guidance

1. Understand that Group 1 elements are alkali metals arranged vertically in the periodic table, starting from lithium (Li) at the top down to cesium (Cs) and francium (Fr) at the bottom.
2. Recall that atomic radius is the average distance from the nucleus to the outermost electron in an atom.
3. Recognize that as you move down a group, each successive element has an additional electron shell compared to the one above it, increasing the size of the electron cloud.
4. Consider that although the nuclear charge (number of protons) increases down the group, the effect of added electron shells causes increased electron shielding, which reduces the effective nuclear attraction on the outermost electrons.
5. Conclude that due to the increased number of electron shells and shielding, the atomic radius increases as you move down Group 1 in the periodic table.