ABSTRACT
The substance we know as water (H2O) is actually comprised of a number of isotopes of O and H. Isotopes are atoms that have the same number of protons and electrons, and therefore the same basic chemical properties, but differ in their mass. Their differences in mass arise due to different numbers of neutrons within their nucleus. Isotopes can be stable or radioactive, and can be both naturally occurring and manmade. Six different isotopes of hydrogen and oxygen are found in nature (Table 1).
