Which factor would be most likely to decrease the atomic radius of an atom?

• A. Reducing the attraction between nucleus and electrons
• B. Increasing the effective nuclear charge
• C. Adding more electron shells
• D. Decreasing the number of protons in the nucleus

Answer: (B)

Verified step by step guidance

1. Understand that atomic radius is influenced by the attraction between the nucleus and the electrons, as well as the number of electron shells.
2. Recognize that increasing the effective nuclear charge means the nucleus has a stronger positive pull on the electrons, pulling them closer and thus decreasing the atomic radius.
3. Consider that adding more electron shells increases the distance between the outermost electrons and the nucleus, which generally increases the atomic radius.
4. Note that reducing the attraction between the nucleus and electrons would allow electrons to be farther away, increasing the atomic radius.
5. Realize that decreasing the number of protons reduces the positive charge in the nucleus, weakening the pull on electrons and increasing the atomic radius.