## Chemistry: The Science in Context (4th Edition)

To name a molecular compound, we keep the name of the first element as-is and only add a prefix to it if there is more than one atom of that element in the compound. For the second element in the compound, we add a prefix to the name of the element reflecting how many atoms of that element are in the compound. We also change the ending to $-ide$. (a) In this compound, there is one hydrogen atom and one bromine atom. HBr is commonly known as hydrogen bromide, but it can also be called hydrogen monobromide. (b) In this compound, there is one carbon atom and two sulfur atoms. We name is carbon disulfide. (c) In this compound, there is one nitrogen atom and three fluorine atoms. Its name is nitrogen trifluoride. (d) We have one phosphorus atom and five atoms of fluorine. Its name is phosphorus pentafluoride.