CHEMISTRY COMMUNITY

How would the size of isoelectronic atoms compare? for example which would be bigger: Ne or Na+? Would this be dependent on nuclear charge?

The Na+ atom would be smaller and the Ne atom would bigger because they have the same number of electrons. However, since Na+ has one more proton, it has a tighter hold on its 10 electrons which makes the atom smaller.

The general rule is that cations are smaller than the noble gas/atom which are smaller than the anions. This is because in cations have more protons in their nucleus, resulting in a stronger attraction that pulls the electrons closer. Anions have fewer protons in the nucleus, so the attraction is weaker and the electrons are not as tightly held by the nucleus.

For isoelectronic atoms, the size would be dependent on the number of protons.