The statement that the first ionization energy for an oxygen atom is lower than the first ionization energy for a nitrogen atom is
A) consistent with the general trend relating changes in ionization energy across a period from left to right, because it is harder to take an electron from an oxygen atom than from a nitrogen atom.
B) incorrect.
C) inconsistent with the general trend relating changes in ionization energy across a period from left to right and due to the fact that the oxygen atom has two doubly occupied 2p orbitals and nitrogen has only one.
D) inconsistent with the general trend relating changes in ionization energy across a period from left to right and due to the fact that oxygen has one doubly occupied 2p orbital and nitrogen does not.
E) consistent with the general trend relating changes in ionization energy across a period from left to right, because it is easier to take an electron from an oxygen atom than from a nitrogen atom.

Question

Quizplus · Accepted Answer

Oxygen has one doubly occupied 2p orbital, which leads to electron-electron repulsion, making it easier to remove an electron compared to nitrogen, which has half-filled stable 2p orbitals.

The Statement That the First Ionization Energy for an Oxygen