5-CinthiaV-Selenium The name of my element is Selenium. The element symbol is “Se”. Selenium was discovered in Sweden by Jons Jacob Berzelius in 1817. Selenium is an origin for a greek word meaning moon. Selenium has four energy levels. In the first energy level, it has two electrons. The second energy level has eight electrons. The third energy level has 18 electrons. The fourth energy level has six valence electrons. Selenium has forty-five neutrons. Selenium has the atomic number of thirty-four. The atomic mass is 78.96 for Selenium. It has 20 isotopes. The most stable isotope is Se (Selenium). Selenium is in the Chalcogen family. The Chalcogen family consists of Oxygen, Sulfur, Selenium, Tellurium, and Polonium.
