Question

the image below tells us that magnesium should be in group ____. (remember to look at the valence shell)
4
2
3
1

Explanation:

Magnesium (Mg) has an atomic number of 12. Its electron configuration is \(1s^2 2s^2 2p^6 3s^2\). The valence shell (outermost shell) is the 3rd shell, and it has 2 valence electrons. In the periodic table, the group number for main - group elements is equal to the number of valence electrons. So Magnesium, with 2 valence electrons, belongs to group 2.

Answer:

2 (the option with "2")