"Beware the Ides of March!"

I know last week I promised to talk on the element manganese, but this week's STEM talk will be devoted instead to the element cobalt.

Per the Wikipedia article, Swedish chemist Georg Brandt is credited with discovering cobalt circa 1735. "The atomic number of [cobalt] is [27]." Co-59 is the only known stable isotope of cobalt. When found in pure form, it is a metallic grey in color; however, it is one of the few metals that is naturally found only in chemically combined form. It is naturally a solid at room temperature (mercury is the only metal that is not solid at room temperature) and has a melting point of 2,723 F.

Cobalt can be a poison. The LD-50 value for soluble cobalt salts has been estimated to be between 150 and 500 mg/kg.

"[...] You type in the code first, then slide the card."