Find the element’s group number on the periodic table
For main-group elements, use the group number to determine valence electrons
Group 1 elements have 1 valence electron
Group 2 elements have 2 valence electrons
Groups 13 to 18 have 3 to 8 valence electrons
Subtract 10 from the group number for groups 13 to 18
For helium, the valence electron count is 2
For transition metals, check the outermost s and d electrons
Write the electron configuration
Count the electrons in the highest principal energy level
Those outermost electrons are the valence electrons