What are valence electrons?
Valence electrons are electrons that can participate in chemical bonds with other atoms. For main group elements, the number of valence electrons is easy to determine: it equals the element’s group number (a Roman numeral you’ll find at the top of the column the element is in, on the periodic table). What are the number of valence electrons for chlorine, oxygen, nitrogen, and carbon? Answer For main group elements, the number of valence electrons follows naturally from the atom’s electronic configuration. In all of these elements, the s and p electrons are valence electrons. In the transition metals, it is possible to have some of the d electrons participate in bonding in addition to the outer s electrons. It isn’t easy to tell by how many d electrons act this way just by looking at the transition metal atom’s electronic configuration. That makes it risky to try to draw Lewis structures for transition metal compounds.
