Question

Which elements does not follow Hund's rule?

Answer 1

Answer:

The number of singly occupied orbitals or unpaired electrons will decrease if Hund's rule is not applied. Total unpaired electrons if Hund's rule is followed is 5. Hence only one electron will be unpaired if this rule is not followed or is not applicable in a NO molecule.

___________________________________

Please mark me as Brainlist

Answer 2

HUND'S RULE -

• The rule to specify the filling of orbitals based on their energy level.
• Hund's rules include -

1. Every orbital is singly filled in a subshell before filling any of the orbital with the second electron.

2. In singly occupied orbitals, the electrons show the same spin.

• Electrons first fill the degenerate orbitals of similar energy.
• The first electron filled can be either spin up or spin down.
• Chromium and copper elements violate Hund's rule.
• In the electronic configuration of the chromium metal, 4 electrons are present in 3d-shell and 2 electrons are present in 4s-shell. To attain stable configuration one electron from 4s is excited to 3d.
• In copper metal, 9 electrons are present in 4d--shell, and 2 electrons are present in the 5s shell and according to Pauli's exclusion principle, one electron from 5s is excited 4d to attain a stable configuration.