Atomic radius generally increases as we move in which direction on the periodic table?

• A. From left to right across a period
• B. From bottom to top within a group
• C. From right to left across a period
• D. From top to bottom within a group

Answer: (D)

Verified step by step guidance

1. Understand that atomic radius refers to the size of an atom, typically measured from the nucleus to the outer boundary of the electron cloud.
2. Recall that as you move from left to right across a period, the atomic number increases, adding more protons and electrons, which pulls the electron cloud closer to the nucleus, generally decreasing atomic radius.
3. Recognize that as you move from top to bottom within a group, new electron shells are added, increasing the distance between the nucleus and the outermost electrons, which increases the atomic radius.
4. Note that moving from right to left across a period means moving toward elements with fewer protons, which generally increases atomic radius, but this is less commonly used as the main trend compared to left to right across a period or top to bottom within a group.
5. Conclude that the atomic radius generally increases from top to bottom within a group because additional electron shells outweigh the effect of increasing nuclear charge.