Among the elements from atomic number 1 to 36, the number of elements which have an unpaired electron in their S subshell is

Options

A. 4
B. 7
C. 6
D. 9

Answer

C

Explanation

`H to 1 s^(1)`
`""_(3)Li to 1s^(2) 2s^(1)`
`""_(11)Na to 1s^(2) 2s^(2) 2p^(6) 3s^(1)`
`""_(19)K to 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(1)`
`""_(24) Cr to 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(1) 3d^(5)`
`""_(29)Cu to 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(1) 3d^(10)`