Avagadro's number is also defined on
12C.
number of atoms in 12g of
12C = 6.0223 x 10
23 atoms.
There are 6.0223 x 10
23 Si atoms, O atoms, N atoms, Fe atoms, Sc atoms, etc., in 12g of
12C. This is conveniently called a mole, as there are also 6.0223 x 10
23 molecules of carbon dioxide, hydrogen fluoride, etc., as well as 6.0223 x 10
23 formula units of NaCl, MgCl
2, etc in 12g of
12C.
Strange how this number of all of these varying sizes of compounds, ionic solids, and atoms fit into 12g of this one atom, but we owe this wonderul constant to the Italian physicist Amedeo Avagadro.
We need those physicists for something.