According to wave mechanics, the specific three-dimensional space around the nucleus that has the highest probability of receiving electrons is called the substratum. n = prime quantum number (indicates major energy level) l = auxiliary quantum number ( indicates sub-energy level) The value of l is from 0 to ( n-1) . m = magnetic quantum number (indicates the number of sub-levels ) m with value 0 (+ -) ls = rotation quantum number ( indicates rotation of electrons) s values of + 1/2 and - 1/2 .