Isotopes

ISOTOPES

Isotopes do not have to be completely unstable. An example is the hydrogen atom. There are three different forms of this element in nature: protium, deuterium, and tritium. The proton number is, of course, the same, while the neutron number changes. There are no neutrons in protium, one neutron in deuterium, and two neutrons in tritium. Figure 3 represents the structure of these three isotopes:

Figure 3.

Carbon also has three isotopes: Carbon-12, Carbon-13, and Carbon-14, representing different atomic masses. The stable form is carbon-12, while carbon-14 is considered radioactive. Other common isotopes seen in chemistry include the following:

• Oxygen—there are three isotopic forms, being O-16, O-17, and O-18

• Uranium—there are two isotopic forms, which are U-235 and U-238

• Chlorine—there are two isotopic forms, which are Cl-35 and Cl-37

• Fluorine—there are three isotopic forms, which are F-17, F-18, and F-19

There are 275 isotopes made from 81 stable elements with more than 800 natural and artificially-created radioactive isotopes. This means that, while there are just 118 elements, many will have different isotopes found. Most isotopes will behave the same chemically, except for hydrogen isotopes because they vary greatly in total weight