Flexi Says: The number of valence electrons in an atom is reflected by its position in the periodic table of the elements. Across each row or period of the periodic table, the number of valence electrons in groups 1–2 and 13–18 increases by one from one element to the next. Within each column or group, all the elements have the same number of valence electrons. This explains why all the elements in the same group have very similar chemical properties
