All chemical elements

Symbol

Se

Atomic number

34

Chemical property

Reactive nonmetal

Origin o the name

the Greek selene, 'moon'

Group

16

Period

4

Atomic weight (u)

78.971

Atomic weight uncertainty (u)

0.008

Density (g/cm³)

4.809

Melting point (K)

453

Boiling point (K)

958

Heat capacity (J/(g·K))

0.321

Electro-negativity

2.55

Abundance in earth's crust (mg/kg)

0.05