Question

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

Answer 1

as mass no -no of neutrons =atomic no so 35-18=17 so as 17 atomic no is of chlorine in periodic table so element X is chlorine.

hope it will help u!!!!

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 ) .