What are Chalcogens?
Chalcogens are the group 16 elements -- oxygen, sulfur, selenium, tellurium, polonium, element 116 -- two columns before the noble gases in a standard periodic table.
The word "chalcogen" comes from the Greek phrase for "copper former" or "ore former". Apart from the more ubiquitous oxygen, they are most commonly found as in the ores of certain metals such as copper. The most common copper ore, for instance, is copper sulfide.