This article analyzes the treatment of chemical elements in six general monolingual explanatory dictionaries. Two approaches are observed with respect to the formation of headword lists: either a complete set of chemical elements is included or only a selection according to the frequency in general language usage. The inventory of hypernyms used as genus words and the degree of systematicity in their usage are presented. Chemical elements represent a reasonable number of lexical units of the same semantic group, therefore a high degree of systematicity of definitions in dictionaries is expected; however, we can only partially confirm this. The use of terminological labels varies greatly from one dictionary to another: in some dictionaries they are not used at all, in others they are used only partially, and in some they are always used. In the case of polysemic entries, one dictionary uses sense indicators.