An atom has electronic configuration 2, 8, 7. (a) What is the atomic number of this element? (b) To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.) N(7), F(9), P(15), Ar(18)
An atom has electronic configuration 2, 8, 7. (a) What is the atomic number of this element? (b) To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.) N(7), F(9), P(15), Ar(18)

(a)The element is Chlorine (Cl) and the atomic number of chlorine is 17.

(b) The atom with the electronic configuration of 2, 8, 7 which is the chlorine is chemically identical to Fluorine (F) which has an atomic number of 9.