Selenium
POLYATOMIC NONMETAL
Phase: Solid
Discovered: Jöns Jakob Berzelius
Block: P
Summary
Selenium is a chemical element with symbol Se and atomic number 34. It is a nonmetal with properties that are intermediate between those of its periodic table column-adjacent chalcogen elements sulfur and tellurium. It rarely occurs in its elemental state in nature, or as pure ore compounds.
Source: WikipediaPhysical Properties
Atomic Mass 78.9718 u
Density 4.81 g/cm³
Melting Point 494 K
Boiling Point 958 K