1.

Identify the element that has the following electronic configuration 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^ 4d^10 5p^6 6s^2 4f^2

Answer»

BA 
At 
CE 
PR 

ANSWER :C


Discussion

No Comment Found