Question

predict the last energy level configurations of the following

Zn
U
Kr
Rb
He
Au
C
Ra

Answer 1

Answer:[Kr] 5s1

Explanation:-

Atomic number of rubidium = 37

Atomic number of Kr = 36

So only 1 electron needs to be assigned an orbital.

Kr is also the last element of the fourth period

So the shell number for the 1 electron will be 5 since it is after Kr

Since s subshell is filled first the electron will go into 5s.

Hence the electron configuration for rubidium (Rb) in noble-gas notation is

[Kr] 5s1

Explanation: