Answer:
From n=1 to n=2
Explanation:
Electrons in n=1 are strongly attracted to the nucleus and therefore will require great force to overcome the electrostatic force of attraction to displace them from the energy level to another.
The electrostatic force reduces as you progress to the outer energy levels.
It posed a contradiction to Quantum Theory
1s^2 2s^2 2p^6 for the Mg2+ ion.
The answer is A lithium sulfite