Why does Phosphorus has more ionization energy than sulfur?

Phosphorus' half filled 3p shell is more balanced stable than Sulfur's 3p shell who has an extra electron counterspinning. So, Sulfur would have a lower 1st ionization energy to get rid of the counterspinning electron than Phosphorus which has a sort of stable half-filled shell. read more

Oxygen has one more electron than Nitrogen and as the orbitals are all half filled the electron must pair up. "According to the hund's rule, electrons will always occupy an empty orbital before they pair up." This should make sense given what you know about electrons. Electrons are negatively charged and, as a result, they repel each other. read more