Question

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

Answer 1

no.if electron 35-18=17= no.of protons
so atomic number will be 17
electronic configuration= 2,8,7


the element is chlorine
it's group number..17

valency -1

hope it helps you
thanks

Answer 2

Atomic no= No of protons

No of protons =35-18=17

*therefore atomic no= 17

*Now electronic configuration is 2 8 7

*Group no is 17

*period no is 3

* the element is chlorine...