Chemistry help!

Question

Helium has a higher Ionization Energy than any other element. What is the cause of this seeing as the nuclear effective charge is only 2? Please explain using the nuclear effective charge why helium has no attraction for an additional electron.

Thank you!

no attraction for an additional electron.

Answer 1

Look at the size (atomic radius). Helium is very small so the electrons are close to the nucleus. There is thus a strong attraction of the positive nucleus and the negative electrons making it difficult to remove the electron.