An atom has the electron structure of 2, 7.

(a) What is the atomic number of this atoms?


(b) To which of the following would it be chemically similar?


7N, 15P, 17Cl, 18Ar


(c) Why would you expect it to be similar?

(a) The election structure is (2,7) so we have to add these electrons to get the atomic number. Therefore the atomic number is 9.

(b) Chlorine which has atomic number 17 is chemically similar.


(c) They expect to be similar because both have same number of valence electron 7.


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