What is a Molecule?
A molecule is two or more atoms chemically stuck together. So, a molecule is like getting two or more scoops of the same flavor of ice cream at the store.
Chemical Symbols
Chemists use symbols to represent elements. A symbol is a letter or picture used to represent something. Chemists use one or two lettters to represent elements. The symbol for aluminum is Al. The symbol for oxygen is O.
Oxygen Molecule
The symbol for oxygen is O. "O" stands for one atom of oxygen. Oxygen stoms are joined in pairs. To write a pair of oxygen atoms using symbols, we use the symbol O and the number 2. Oxygen would be (O2). The 2 is a subscript. "Sub" means "below". The 2 is written to the right of and below the O. A pair of oxygen atoms is a molecule of oxygen. A molecule is the smallest particle of a substance that exists independently. Molecules of most elements are made up of only one of atom of that element. Oxygen, along with nitrogen, hydrogen, and chlorine are made up of two atoms. Look at the model of oxygen above. The two balls represents the two oxygen molecules. The oxygen molecules are bonded or stuck together.