From Mass Spectrometry Terms
--Ionworker 11:58, 6 Jan 2005 (CST)
I think a dimensionless quantity should not be called a mass. Therefore mass number should be discontinued. Also, nucleon number is more precisely describing what is meant.
Moved from front page:
| The nucleon number is the number of nucleons in a molecule.
It is a unitless physical property with symbol N.
|This is a Draft Definition. If you would like to know more about the current definitions of mass spectrometry terms, please see the IUPAC Orange Book.|
|The corresponding Wikipedia page (if any) is Nucleon number|
There used to be another name for the same property: the Mass number. This name, however, is misleading because a unitless quantity should not be called "mass". The symbol for the quantity nucleon number used to be m, which is even more unfortunate because m is the official symbol of a mass quantity.
- M = z Da
where z is an integer value.