Question

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)

Answer 1

Explanation:

a) 17 is the atomic number

b) Ar(18) because both will have same number to electrons as a stable

Answer 2

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(a)The element with electronic configuration (2+8+7) 17 is chlorine.

The no. of atomic number = no. of electrons

Therefore, atomic number is 17.

(b) An atom with electronic configuration 2, 8, 7 would be chemically similar to F (9)