Britannica Sources used in this answer

When were the relationships among oxygen, sulfur, and selenium first recognized?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — oxygen group element Modern version of the periodic table of the elements (printable).

The relationships among oxygen, sulfur, and selenium—the first three members of the oxygen group element family—were first recognized as early as 1829.1