Key Concepts
- Ionization energies
- Electron configuration
The electron configuration of Mg is 1s²2s²2p⁶3s².
Second Ionization Energy: When we take away two electrons from Mg, it loses its 3s orbital and gains a full 2p orbital: 1s²2s²2p⁶. Mg has 2 valence electrons, and taking them away has allowed it to gain a full valence shell. Here, it is very stable.
Third Ionization Energy: Now that Mg is in a very stable state, it's going to be very difficult and require a lot of energy to remove another electron.