Each ammonia molecule contains one atom of nitrogen and three atoms of hydrogen. We know this because the hydrogen symbol has a subscript three after it, whereas the nitrogen symbol has no number ...

Symbol: A one or two-letter abbreviation used to represent the element. Atomic number: The number of protons in the nucleus of an atom of the ... sequentially from 1 (Hydrogen) to 118 (Oganesson).

join with another hydrogen atom as a pair, making a molecule. Sometimes it is easy to tell which element a symbol stands for. For example, C stands for carbon and Li stands for lithium.