Selenium is a nonmetal with light-sensitive electrical properties and a narrow but essential biological role.
Atomic number
34
Category
Reactive nonmetal
Period
4
Group
16
State
Solid
Fun facts about Selenium
Its electrical conductivity increases when illuminated.
Selenium is essential in trace quantities but harmful in excess.
It can replace sulfur in related chemical compounds.
Common uses of Selenium
Glass decolourising and colouring
Photovoltaic materials
Nutritional supplements where deficient
Where Selenium sits in the periodic table
Selenium is classified as a reactive nonmetal in period 4 and group 16 of the periodic table. Under the conditions represented in this reference, its state is solid.
Quick chemistry revision
For quick revision, pair the symbol Se with atomic number 34 and the listed atomic mass 78.971. The summary, facts, and uses above keep those element properties together in one reference.