The shielding of electrons gives rise to an effective nuclear charge, Z_eff, which explains why boron is larger than oxygen. Estimate the approximate Z_eff felt by a valence electron of boron and oxygen, respectively?

Calculate Z_eff for a 3d electron in a copper atom, Cu.

What trend in atomic radius occurs down a group on the periodic table what causes this trend?

What trend in atomic radius occurs down a group on the periodic table? What causes this trend?

Rank the following elements by effective nuclear charge, Z_Eff, for a valence electron: Kr, Se, Ca, K, Ge