question_answer

The valence of representative elements is either equal to the number of valence electrons or eight minus this number. Explain.

Answer:

                The representative elements belonging to s and p-blocks tend to have noble gas configuration of their atoms. To achieve this, they do so either by losing the valence electrons or gaining electrons which is equal to eight minus the number of valence electrons. For example, valence of sodium (Z = 11) is one because it has one valence electron (2, 8, 1) which it loses to have the configuration of neon. Similarly, the valence of chlorine (Z = 17) is also one because it has seven valence electrons (2, 8, 7) and accepts one electron (8 - 7 = 1) to have the configuration of nearest noble gas element argon.