Which of the following periodic trends is inversely proportional to effective nuclear charge?

• A. Electronegativity
• B. Atomic radius
• C. Ionization energy
• D. Electron affinity

Answer: (B)

Verified step by step guidance

1. Understand the concept of effective nuclear charge (Z_eff), which is the net positive charge experienced by an electron in an atom. It accounts for the actual nuclear charge minus the shielding effect of inner electrons.
2. Recall that effective nuclear charge generally increases across a period from left to right on the periodic table because the number of protons increases while shielding remains relatively constant.
3. Analyze how effective nuclear charge affects each periodic trend: Electronegativity, Ionization energy, Electron affinity, and Atomic radius.
4. Recognize that as effective nuclear charge increases, electrons are pulled closer to the nucleus, which decreases the atomic radius. Therefore, atomic radius is inversely proportional to effective nuclear charge.
5. Conclude that among the given options, atomic radius decreases when effective nuclear charge increases, making atomic radius the periodic trend inversely proportional to effective nuclear charge.