An element X has mass number 35 and number of neutrons = 18. Write atomic number and electronic configuration of X. Also write group number, period number and valency of X.

Explanation

Atomic number of X = Mass number of X - No of neutrons
= 35 - 18 = 17
Therefore, Electronic configuration of
X = 2, 8, 7
Group number = 17
Period = 3
Valency = 8 - 7 = 1