Selenium (Se), element 34 – Learn Acer periodic table

Selenium

Nonmetal, atomic number 34.

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.

Facts

Symbol Se. Atomic mass 78.9718 u. Group 16, period 4. Electron configuration [Ar] 3d10 4s2 4p4. Electrons per shell 2, 8, 18, 6. State at room temperature: Solid. Melting point 220.9 °C, boiling point 684.9 °C. Discovered by Jöns Jakob Berzelius.

Element data from Wikipedia, CC BY-SA 3.0.