There is a recurring history in the literature of noting a comparable range of metal and non-metal types, from highly reactive to less reactive, even noble. For example: What, in general, is the difference between active metals, less active metals, less active non-metals, active non-metals, and inert gases…? By the end of 8th grade, students should know that… there are groups of elements that have similar properties, including highly reactive metals, less reactive metals, highly reactive nonmetals (such as chlorine, fluorine and oxygen) and some almost completely unreactive gases (such as helium and neon). Or more recently: