Concept preview

What you will be able to do

1. 01Name binary molecular compounds using prefixes
2. 02Recognise and name common acids
3. 03Choose the correct naming method for any formula

When two different nonmetals combine, the compound is molecular and is named with Greek prefixes that state how many of each atom are present. The prefixes are mono (1), di (2), tri (3), tetra (4), penta (5) and hexa (6). The first element keeps its name with a prefix; the second takes an '-ide' ending with a prefix. So $\mathrm{P_2S_3}$ is diphosphorus trisulfide, $\mathrm{CS_2}$ is carbon disulfide, and $\mathrm{N_2O_4}$ is dinitrogen tetroxide.