Hyphen notation:
The isotope is written with the chemical name, followed by a hyphen and atomic mass. For example, carbon-12, carbon-13, and carbon-14 are all isotopes of carbon.
Isotopic notation (nuclear symbol):
The A number is placed to the upper left corner of the chemical symbol. For example, 12C, 13C, and 14C. Many texts also include the Z number in the bottom left corner of the chemical symbol. Additionally, ions may need a charge placed to the right of the chemical symbol.
You may want to add information to this page: http://www.thechembook.com/wiki/index.php/Isotopes

Hyphen notation:

The isotope is written with the chemical name, followed by a hyphen and atomic mass. For example, carbon-12, carbon-13, and carbon-14 are all isotopes of carbon.

Isotopic notation (nuclear symbol):

The A number is placed to the upper left corner of the chemical symbol. For example, 12C, 13C, and 14C. Many texts also include the Z number in the bottom left corner of the chemical symbol. Additionally, ions may need a charge placed to the right of the chemical symbol.

You may want to add information to this page: http://www.thechembook.com/wiki/index.php/Isotopes