Question

Which Ion has the same electron configuration as an Ar atom
1. Cl -
2. F -
3. Li+
4. Na +

Answer 1

Ar (argon) has 18 electrons

Cl- would give you 18 electrons
F- would give you 10 electrons
Li+ would give you 2 electrons
Na+ would give you 10 electrons

Cl- would be the correct answer