Tom Skerritt. Biography: Tom Skerritt is probably the best-known actor whose name is never remembered. A rugged outdoors type, Skerritt briefly attended Wayne State University and UCLA before making his film bow in [[Feature~V115961~War Hunt~warhunt]] (1962). His...
The chemical formula for oxygen is O2 and for individual oxygen  atom its symbol is O.   Gases such as oxygen exist as diatomic molecules.
What does the chemical formula tell us? The formula H20 tells us that one molecule of water is comprised of 2 atoms of hydrogen and one atom of oxygen bonded together. The bonds which hold the hydrogen and oxygen together are called covalent bonds - they are very strong.