1. the first element in the formula is named first, using the full element name.
2. the second element is named as if it were an anion.
3. prefixes are used to denote the numbers of atoms present. These prefixes are shown in the left table.
4. The prefix mono- is never used for naming the first element. For example, CO is called carbon monoxide, not monocarbon monoxide.
N2O: Dinitrogen monoxide
NO: Nitrogen monoxide
NO2: Nitrogen dioxide
PCl5: Phosphorus pentachloride
SO2: Sulfur dioxide