Which of the following transition metals would be predicted to have the smallest atomic radius?

• A. Fe
• B. Zn
• C. Mn
• D. Cu

Answer: (B)

Verified step by step guidance

1. Step 1: Understand that atomic radius generally decreases across a period from left to right in the periodic table due to increasing nuclear charge, which pulls electrons closer to the nucleus.
2. Step 2: Identify the position of each element (Fe, Mn, Cu, Zn) in the periodic table. All are transition metals in the 4th period, but their atomic numbers increase from Mn (25), Fe (26), Cu (29), to Zn (30).
3. Step 3: Recognize that as you move from left to right across the transition metals, the effective nuclear charge increases, which tends to decrease the atomic radius.
4. Step 4: Consider that Zn has a completely filled d-subshell (3d10), which leads to a stronger effective nuclear charge and less electron-electron repulsion compared to the others, resulting in a smaller atomic radius.
5. Step 5: Conclude that among the given options, Zn would have the smallest atomic radius due to its position furthest to the right in the period and its filled d-subshell configuration.