Question

An element "X" has mass number 35 and the number of neutrons, is 18. find the group number and period of "x"..

Answer 1

Group=35-18=17
Electronic configuration =2,8,7
So group=17 and period=3

Answer 2

Answer:

We know :

Atomic number = Mass number - No. of neutrons.

Atomic number = 35 - 18

= > 17

Electronic configuration :

2 , 8 , 7

Group no. = 17

Period no. = 3

Name of element is Chlorine (  Cl ) .