[Kalyani Gupta]

Kalyani Gupta asked the Naked Scientists:

Why don't all the elements have the same number of isotopes?

What do you think?

[chris]

Hi Kalyani

This is to do with the stability of the nucleus. Isotopes are forms of the same element with different numbers of neutrons. In other words the atoms of different isotopes have the same number of protons and electrons but weigh a slightly different amount because they have different numbers of neutrons in the nucleus.

However, not all combinations of protons and neutrons are stable and when this happens the nucleus falls apart producing a new element before any appreciable amount of the substance can ever accumulate. This is effectively what is happening when a radioactive isotope decays.

Chris