ABSTRACT
Every electron possesses an intrinsic ½ unit of angular momentum. This is a fundamental property of the electron, like its mass and charge, that cannot be altered. The spin angular momentum may be clockwise or anticlockwise corresponding to two quantum states with electron spin quantum number, ms=+½ and −½. The two spin states of an electron are often represented by the symbols ↑ and ↓, respectively. When electron spins are paired (↑↓) there is zero net spin angular momentum because the spin angular momentum of one electron is cancelled by the opposite spin angular momentum of the other electron.
