How does atomic radius change from left to right across a period in the periodic table?

• A. Atomic radius increases.
• B. Atomic radius decreases.
• C. Atomic radius first increases, then decreases.
• D. Atomic radius remains constant.

Answer: (B)

Verified step by step guidance

1. Understand that atomic radius refers to the size of an atom, typically measured as the distance from the nucleus to the outermost electron cloud.
2. Recall that as you move from left to right across a period in the periodic table, the number of protons in the nucleus increases, which increases the nuclear charge.
3. Recognize that the increased nuclear charge pulls the electrons closer to the nucleus, reducing the size of the electron cloud despite electrons being added to the same energy level.
4. Note that because electrons are added to the same principal energy level, the shielding effect remains relatively constant and does not offset the increased nuclear charge.
5. Conclude that due to the stronger attraction between the nucleus and electrons, the atomic radius decreases from left to right across a period.