Chromium has six valence electrons. The atomic number of chromium is 24, and its electron configuration is 1s22s2 2p63s23p63d54s1 or 2, 8, 13, 1 electrons per shell. The electrons in the 3d54s1 shells form the valence electrons as the five electrons in the 3d shell participate in chemical bond formation.
Louis-Nicholas Vauquelin discovered chromium in 1797. The symbol of chromium is Cr, and fresh chromium is lustrous. It is a bluish white transition metal at room temperature, and is placed in Group 6 or d-block and Period 4 of the periodic table of elements. It is hard, brittle and does not corrode easily. It can be used to form a protective coating over other metals due to its anti-corrosive property. The atomic weight of chromium is 51.6661 atomic mass units, and its melting point is 3465 degrees Fahrenheit. The density of chromium is 7.15 grams per centimeter cubed.
Chromium has multiple valences, and this is due to the fact that it has three oxidation states of +6, +3 and +2. Many of the compounds of chromium are intensely colored; hence the name "chroma," which means color. Chromium has three isotopes. It is extracted from its iron ore called chromite or FeCr2O4.