Answer: Heyo Kenji Here! Here's your answer- Mg =1s2 2s2 2p6 3s2 = [Ne]3s2, therefore magnesium has 10 core electrons from its 1s2, 2s2, 2p6 orbitals. Magnesium is element 12, so it has 12 protons and a nuclear charge of 12.
Explanation: Hope this helps!
Have a nice day!
- Kenji ^^