Valence Electron

The valence shell is the outermost layer of an atom. Electrons in this shell are called valence electrons.

The number of valence electrons of non-transition metals can easily be found by their location in the periodic table (Figure 1).

The view of periodic table with valence numbers for elements in group 1,2 and from groups from 13 to 17. All Elements in group 1 have valence number 1. All Elements in group 2 have valence number 2. All Elements in groups 13, 14, 15, 16 and 17 have valence numbers 3, 4, 5, 6, and 7, respectively. All elements in group 18 have valence number 8, except Helium, with valence number 2.

Figure 1: Valence electrons of elements in group I to VIII