Question

Among the elements from atomic number 1 to 36 the number electrons which have an unpaired electron in their s - subshell

Answer 1

Dear Student,

Elements from atomic number 1 to 36 are from Hydrogen (H) to Krypton (Kr) which includes 1 to 4 period elements and all 18 groups.
The four elements of group 1 do contain ns¹ electrons, also Cr and Cu contains an unpaired electron in s-orbital.
​Therefore, total 6 elements contains unpaired electron in s-orbital.