1.

A natural atom of an element has `2K,8L, 9M` and `2N` electrons .The atomic number of element is : The valency of element isA. `+2`B. `+3`C. `Both +2 and +3`D. `-1`

Answer» Correct Answer - C
`overset(2K,8L,9M,and,2N)underset(1s^(2),2s^(2)p^(6),3s^(2)3p^(6)3d^(1), 4s^(2))`
`({:(K means n = 1, l means n = 2),(M means n = 3 , N means n = 4):})`
`"Structure is" `3d^(1),4s^(2)`
Atomic number 21
Structure is `3d^(4),4s^(2)`
So `e^(bar)` can be excited from `4s` and `3d` both (since energy difference between `3d` and `4s` very very small ) So, veloncy is `+ 2` and `+3` both


Discussion

No Comment Found

Related InterviewSolutions