Magnetic quantum number

              The magnetic quantum number is the third set of quantum numbers which describe the unique quantum state of an electron. It is denoted by letter m_{l . The magnetic quantum number denotes the energy levels available with in a subshell.}  m_{l  can take value from -l to +l.}

• l=0 . s orbital has only one subshell. Therefore the m_{l of an electron in an s orbital will always be 0 ( m=0 ).}
• _{l=1. p orbital has three subshells. Therefore the} m_{l of an electron in an p orbital will be}           m_{l = -1,0,+1. This would represents the three different orientations in p orbital. They are usually defined as px, py, pz.}
• l=2. f orbital has five subshell. Therefore the m_{l of an f orbital will be}  m_{l = -2, -1, 0, +1, +2}