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Atoms and Atomic Structure

Explain how two isotopes of an element are different?


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April 23, 2011 2:11AM

An isotope of an element is simply an element with the same number of protons, but with a different number of neutrons. Since the proton count establishes elemental identity, chemical traits of different isotopes of the same element tend to be the same. The different number of neutrons, however, affects the stability and mass of the nucleus, sometimes creating a radioactive isotope, sometimes creating a non-radioactive (or stable) isotope.

The atomic number is the number of protons. The atomic mass number is the number of protons plus the number of neutrons. The atomic mass, however, is not integral, because it includes everything, including the electrons, and none of them have the same mass.