- Negative ions are formed among atoms of non-metal elements except group-18 elements.
- Non-metal elements usually located in group 15, 16 and 17 in the periodic table and have 5, 6 or 7 valence electrons.
- To achieve octet arrangement of electrons, their atoms will receive 3, 2 or 1 electron.
- As a result, the electrons will out number the protons and hence negative ions formed.
Formation of Negative Ions of -1 Charge
|(A fluorine atom receives one electron to form a fluoride ion with -1 charge)|
Formation of Negative Ions of -2 Charge
|(An oxygen atom receives two electrons to form a oxide ion with -2 charge)|