Name:  Selenium

Atomic Symbol and Mass Number: Se [34]

Electron Configuration: [Ar] 3d  4s  4p

Atomic Radii: 190 pm

Electron Affinity: 195 kJ mol-1

Oxidation states: −2, +4, +6

Electronegativity value: 2.55

Elemental Group: Chalcogen

Uses and properties:

• Most stable form is a metallic gray crystalline hexagonal selenium

• Crystalline monoclinic selenium is a deep red color

• Amorphous selenium is red in powder form and is black in vitreous form

• Metallic selenium is photoconductive and photovoltaic

• Used in the glass industry to decolorize glass and to make red-colored glasses and enamels

• Catalyst in chemical reactions

• Solar cells and photocells, as well as photographic toner

• Used with bismuth in brasses and as an additive to stainless steel

• Selenium sulfide is used in anti-dandruff shampoos

 

Lewis diagram: