Selenium was discovered by Jöns Berzelius at 1817 in Sweden.
Origin of name: from the Greek word "selene" meaning "moon".
Atomic Number: 34
Atomic Weight: 78.96
Melting Point: 493.65 K (220.5°C or 428.9°F)
Boiling Point: 958 K (685°C or 1265°F)
Density: 4.809 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Non-metal
Period Number: 4 Group Number: 16 Group Name: Chalcogen