Questions About Atoms: Protons & Neutrons

[fluidistic]

How did we know that the more common isotope of iron has 26 protons and 30 neutrons?
I'm asking a general question so the iron example is just a special case.
How did we know that oxygen has 8 protons? (and 8 neutrons), and also that the 8 neutrons is the most stable isotope and that there exists other isotopes in smaller quantities. How did we determine the quantities of the isotopes?

 

[malawi_glenn]

mass spectroscopy = charge vs. mass

 

[fluidistic]

Thanks a lot. I wasn't aware of this.

 

[malawi_glenn]

http://books.google.com/books?id=XyW97WGyVbkC&pg=PA1&dq=nuclei+particle&hl=sv#PPA15,M1

page 15

 

[fluidistic]

http://books.google.com/books?id=XyW97WGyVbkC&pg=PA1&dq=nuclei+particle&hl=sv#PPA15,M1

page 15

Thank you very much, this is very informative.