## Chem – Quantum Numbers (Part 4)

What sections should I know before attempting to learn this section?

What does the ms stand for in the quantum numbers?

The last quantum category is ms (It is pronounced “M sub S”) represents what they call the spin. It is the easiest to figure out and the easiest to understand. Just like in the electron diagrams we used an up and a down arrow to represent the electrons traveling different directions within the same orbital. Here instead we use +1/2 and -1/2 to represent the up and down respectively. You can honestly choose these things at random so long as no two electrons in a row (within the same orbital) have the same ms. You can put them in a specific order on the periodic table but it does not matter that much. I usually put +1/2 first. This is one example of a periodic table where the electron spin is illustrated.

Examples: Give the ms for the last electron in the following elements. (These do not have definite answers but I give the answer I do because of the way I have explained them to you.)

 Be ms = -1/2 Pd ms = -1/2 Al ms = +1/2

PRACTICE PROBLEMS: Give the ms for the last electron in the following elements. (These do not have definite answers but I give the answer I do because of the way I have explained them to you.)

 Bi ms = +1/2 F ms = -1/2 Ni ms = -1/2 Li ms = +1/2  