Chromium

Into the world of CHROMIUM

Information

History

The element chromium was discovered in 1797 by Louis-Nicholas Vauquelin. He made his discovery when he mixed Crocoite and Hydrochloric acid.

Properties

Chromium is a very hard and brittle metal. Its color is a bluish silver. The metal Chromium is also very corrosion resistant.

Uses

Can be polished to a shiny surface. Often used as a surface for cars.

Used to make brick molds because of chromium's high melting point.

Added to other metals to harden them.

Compounds

Lead Chromate- (PbCro4) Yellow pigment in paint.

Chomic Oxide- (Cr2O3) Green pigment in paint.

Potassium dichromate- (K2Cr2O7) Used in the tanning of leather.

Periodic Table

Atomic Number and Mass

The atomic number for Chromium is 24.

The Atomic mass of Chromium is 51.9961.

Number of each Particle

24 Protons

28 Neutrons

24 Electrons

Notation

Nuclide Notation- 51.99

24 Cr

Hyphen Notation- Cr- 51.99

Model

Visual Model

Valence Electrons

1 Valence electron

Lewis Dot

  • Cr

Group

Group Name

Transition Metals

Group Properties

  • Good conductors of heat and electricity
  • Malleable
  • Less reactive than alkali metals
  • High melting points- 3,465 F
  • High densities
  • Usually high and tough

Reaction Type

Chromium Oxide

Synthesis Reaction

(2Cr+3O yields Cr2+ O3)

Mole Ratios : 2 Mol Cr : 3 Mol O 2 Mol Cr: 1 Mol Cr2O3

Bonding

Chemical Formula

Chromium oxide's formula is CrO

Bonding Type

Ionic Bonding

Percent of Each Element

67% Chromium

33% Oxygen

Creativity

Acrostic Poem

Chrome

High density

"mirRor like reflection" when polished

Opaque

used to Make stainless steel

relatIvely hard

U

alMost never found in its elemental state in nature

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