An element has outermost shell configutation 4s2,4p3 (a) find the atomic number of element place below it (b) next noble gas no.

Dear Student,
Given electronic configuration belongs to  Arsenic element. with atomic number 33
[Ar] 3d10 4s2 4p3

For finding atomic number paced below just 18 to it 
so 33 + 28 = 51 which belong to antimony (Sb).
Next noble gas is Kr(36).


Regards