It takes 208.4 kj of energy to remove 1 mole of electrons from 1 mole of atoms on the surface of rubidium metal. how much energy does it take to remove a single electron from an atom on the surface of solid rubidium?

3.46*10⁻²² kJ

Explanation:

By the Avogadro's number, 1 mole of electrons at 1 mole of atoms correspond to 6.02x10²³ electrons. So it's necessary 208.4 kJ to remove 6.02x10²³ electrons. To remove a single electron:

6.02*10²³ electrons 208.4 kJ

1 electron                   x

By a simple direct three rule:

6.02*10²³ x = 208.4

x = 3.46*10⁻²² kJ