|
| |
Carbon-12
|
| |
12
|
| |
C
|
| |
6
|
| |
6
|
| |
989%
|
| |
12
|
| |
0+
|
| |
0000
|
| |
0000
|
| |
92161753
|
| |
0014
|
is the more abundant of the two stable
Isotope s of the element
Carbon , accounting for 98.89% of stable carbon isotopes in the
Natural Environment . It contains 6
Protons , 6
Neutrons and 6
Electrons .
Carbon-12 is of particular importance as it is used as the standard from which all other isotopes'
Atomic Weight is measured and thus the measurement of
Avogadro's Number .
Prior to
1959 both the
IUPAP and
IUPAC tended to use used
Oxygen to define the mole, the chemists defining the mole as the number of atoms of oxygen which had mass 16 g, the physicists using a similar definition but with the
Oxygen-16 isotope only. The two organizations agreed in
1959 /
1960 to define the mole as:
''"The mole is the amount of substance of a system which contains as many elementary
''entities as there are atoms in 0.012 Kilogram of carbon 12; its symbol is "mol.""''
This was adopted by the
CIPM (International Committee For Weights And Measures) in
1967 , and in
1971 it was adopted by the 14th
CGPM (General Conference On Weights And Measures) .
In
1980 the CIPM clarified the above definition, defining that the carbon-12 atoms are unbound and in their
Ground State .
