question_answer

Krypton \[{{(}_{36}}Kr)\] has the electronic configuration \[{{(}_{18}}Ar)\] \[4{{s}^{2}},3{{d}^{10}},4{{p}^{6}}\]. The \[{{37}^{th}}\] electron will go into which one of the following sub-levels [CBSE PMT 1989; CPMT 1989; EAMCET 1991]

A)                 \[4f\]    

B)                 \[4d\]

C)                 \[3p\]   

D)                 \[5s\]