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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?
Solution
(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.
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