SolutionsGetting Closed Shells
1. How many extra or missing?
How many electrons does each atom have in excess, or lack, to have a closed shell?
- Li
- Mg
- O
- Cl
- Li: 1 extra (it gives it up).
- Mg: 2 extra (it gives them up).
- O: 2 missing (it accepts or shares them).
- Cl: 1 missing (it accepts or shares it).
2. Noble gases
Why do helium, neon and argon hardly form any compounds?
Because their outermost shell is already closed, a very stable situation: they do not need to give up, accept or share electrons.