Question

In a given transition series, the atomic radius does not change very much with increasing atomic number. Explain.

Answer 1

1. Nuclear charge increases across the series, tending to pull electrons closer.
2. Added electrons enter the (n − 1)d subshell and do not fully shield outer electrons.
3. Increasing d‑electron shielding roughly balances the stronger nuclear pull, so radius changes little.
4. Near the end, increased electron pairing raises repulsion and may slightly expand the size.