Why is there an
abundance of
even atomic number elements vs
odd ones?
The answer is (drum roll please):
Helium Burning
Basically, once particles cooled to actually form
nuclei, a quick chain of nuclear (
fusion) reactions occured:
2
1H-->
4He
The following reactions the occured:
3
4He-->
12C
12C+
4He-->
16O
16O+
4He-->
20Ne
etc etc...
Thus, as
helium reacted with other, primarily even numbered nucleii, the even numbered elements showed an increase in abundance compared to the odd elements.
Note:
Iron (
26Fe) is the most stable of elements, hence it's greater abundance compared to surrounding elements.