Question

what is incorrect about this orbital diagram?
both arrows in the 2p box should be pointing up
there should be 1 electron (arrow) in the first 2p box and one in the 2nd 2p box
there is nothing incorrect with this diagram
all the arrows should be pointing up.

Explanation:

Step1: Apply Hund's Rule

Hund's rule states that electrons will fill degenerate orbitals (same - energy orbitals, like the three \(2p\) orbitals) singly before pairing up. In the \(2p\) sub - shell, there are three orbitals. For the \(2p\) electrons, we should first put one electron in each of the first two \(2p\) orbitals with parallel spins (arrows pointing in the same direction) before pairing.

Step2: Analyze the given diagram

In the given \(2p\) orbital diagram, both electrons are put in the first \(2p\) orbital. According to Hund's rule, there should be 1 electron (arrow) in the first \(2p\) box and one in the 2nd \(2p\) box before pairing.

Answer:

There should be 1 electron (arrow) in the first \(2p\) box and one in the 2nd \(2p\) box.