Published: November 26, 2020 9:03am EST The periodic table of the elements, principally created by the Russian chemist, Dmitry Mendeleev (1834-1907), celebrated its 150th anniversary last year.

Eleven non-metals are gases at room temperature, including oxygen and chlorine. One non-metal, bromine, is a liquid at room temperature. The other non-metals are solids at room temperature ...