Answers

2016-03-09T21:10:09+05:30
Helium has 0 valency because the electron is 2 for helium and  the outer most shell is fully filled .... that is K shell contain 2 , so the valency is 0 for helium and it is known as noble gases or inert gases . its has extremely low reactive .
 
                      HOPE YOU LIKE IT ............. BEST OF LUCK ......
                                              THANK YOU ..........^-^
 
1 4 1
2016-03-10T07:31:56+05:30
Helium atomic no s 2 n itz electronic configuration s 2 which has oly 1 shell I.e., "K"....n itz has capacity 2 hold oly 2 electronz. in helium, diz shell s completely filled so it gained octate law. hence it s noble gas having 0 valency....

SAM:)
cheerz!!!!
1 5 1