Answer to Question #127074 in Physics for Susan Williams

Question

What are the similarities and differences between the isotopes of an element?

Answer 1

By definition, the isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. This means that all isotopes of the same element contain the same number of protons in their nuclei, but different numbers of neutrons. For example, the different isotopes of carbon may contain 6, 7 or 8 neutrons but all of them contain 6 protons.

As far as only proton is a charged particle, this similarity leads to the equal number of electrons in the corresponding atom. Thus, all isotopes of the particular element demonstrate similar chemical proprieties.

Contrariwise, the difference in neutron number leads to the different stability of isotopes nuclei. For example, carbon isotopes with 6 and 7 neutrons are stable, but the isotope with 8 neutrons is radioactive.