- #1

SteveDC

- 39

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**I have the solution for this problem but don't understand it.**

1. Homework Statement

1. Homework Statement

Use Hund's rules to calculate the ground state of erbium with electron configuration [Xe]4f

^{12}6s

^{2}

## Homework Equations

Hunds Rules:

1. Maximise S (within Pauli)

2. Maximise L (within Pauli)

3. Min J (for less than half-filled orbitals) or Max J (for more than half-filled orbitals)

## The Attempt at a Solution

So I used these rules on the 12 electrons in unfilled f orbital and I arrived at S=1, L=5, and therefore J=S+L=6 but the solution which I have been given is: S=3, L=9, J=12

Can anyone confirm if the solution is correct and where I am going wrong?

Thanks