Question

An atom has the electron structure of 2, 7.
(a) What is the atomic number of this atom?
(b) To which of the following would it be chemically similar?
₇N, ₁₅P, ₁₇Cl, ₁₈Ar
(c) Why would you expect it to be similar?

Answer 1

(a)  The atomic number of the atom is 9 (electronic configuration 2, 7), since it is the sum total of the electrons present in an atom.

(b) The atom would be chemically similar to ¹⁷Cl (electronic configuration 2,8,7).

(c) They are similar because both have the same number of valence electrons (7) in their atoms.