Radical (Chemistry)

In Chemistry a radical (or free radical) is a single atom that usually exists in a diatomic molecule (for example, oxygen). Because the other atom in the molecule has reacted with something, the radical is left alone and uncharged, and thus it is very hard for that molecule to react. There is only one way for a radical to gain enough energy to react in nature - a lightning strike (similar to in the Nitrogen cycle). This will cause to to re-react with its original partner (and nothing else) and form another diatomic molecule.