The following are hypothetical configurations for a

Question

The following are hypothetical configurations for a beryllium atom.

1. 1s²1p²

2. 1s¹2s³

3. 1s¹2s¹2p²

4. 1s²2s¹2p¹

5. 1s²2s²

6. 1s³2s¹

^{a) Which use nonexistent orbitals? Select all possible answers ?}

^{b) Which are forbidden by the Pauli principle? Select all possible answers ?}

^{c) Which are excited states? Select all possible answers ?}

^{d) Which is the ground state configuration?}