ST. LOUIS -- When the Boston Red Sox signed Mike Napoli this past winter, there were a number of possible outcomes. He could hit a little, the way he had in 2012, putting up an OPS+ of 113. He could hit a lot, like he had in 2011, with a 173 OPS+ and 30 home runs. Most likely, he'd fall somewhere in between.
The fourth quantum number is the spin quantum number, s. There are only two values for s, +Â½ and -Â½. These are also referred to as 'spin up' and 'spin down'. This number is used to explain behavior of individual electrons as if they were spinning in a clockwise or counterclockwise.
The quantum number m can assume 2 l + 1 values for each value of l, from â l through 0 to + l. When l = 0 the only possible value of m will also be zero, and for the p orbital (l = 1), m can be â1, 0, and +1. given orbital is characterized by a fixed set of the quantum numbers n, l, and m. The electron spin itself constitutes a fourth quantum number s, which can take the two values +1 and â1.