Question

2

Which of the following notations is the correct noble gas configuration for Sr?
OA. [Ar]4s2
OB. [Ar]5s2
OC. [Kr]4s2
OD. [Kr]5s2

Answer 1

D

Step-by-step explanation:

we use noble gas configuration of Kr because Kr atomic number is nearest to Sr

the atomic number of Kr and Sr

is equal to 36 and 38 based on this we write the electron configuration

1s2 ,2s2 , 2p6 , 3s2 , 3p6 , 4s2 , 3d10 , 4p6 === Kr and 5s2