Originally Posted by Kestrel
Correct. The outer electron is lost, and there are now 21 protons to attract 20 electrons, so it pulls them in closer.
But I'm having difficulty with Ca < Sc in the non-ion. Even though Sc has more elections and occupies another subshell, the atomic radius anywhere I can find looks to be smaller. Is this because it has another proton, and therefor, more pull?