How is the number of valence electrons related to the ionization energy of an element?

Within the same period (or row) of the periodic table, ionization energy increases fairly smoothly as the number of valence electrons increases. ... When going from Family 2 to Family 13 (Be to B, or Mg to Al) the ionization energy drops by about 110 kJ/mol.Sep 20, 2015 read more

The number of valence electrons is related to the ionization energy of an element such that when there is few valence electrons, the ionization energy of an element is lower. The trend on the periodic table follows that the ionization energy fairly increases as the number of valence electron increases. read more

When going from Family 15 to Family 16 (N to O, or P to S), the ionization energy drops by about 90 kJ/mol. This can be attributed to "correlation energy," the energy required to get two electrons to share an orbital. In Family 15, all p-electrons are alone in their orbitals; in Family 16, two of the four p-electrons must share an orbital. read more