Chromium is a chemical element its atomic number is 24. Its atomic mass is 51.99 amu and it is represented by the symbol Cr. It is a d-block transition metal with a silvery metallic appearance. In the periodic table, it is in group 6, and period 4. Its electronic configuration is 1s2, 2s2, 2p6, 3s2, 3p6, 4s1, 3d5. Chromium is a hard and solid metal at STP. Its melting point is 2180 K ?(1907 °C, ?3465 °F) and its boiling point is 2944 K ?(2671 °C, ?4840 °F). Its electro negativity is 1.66 (Pauling scale). The oxidation states of chromium is −4, −2, −1, 0, +1, +2, +3, +4, +5, +6 depending on the oxidation state of reaction atom. Chromium has three stable isotopes Chromium-52, Chromium-53 and Chromium-54. It was discovered by French chemist Louis Nicolas Vauquelin in 1797.
At ground state, the electronic configuration of Chromium violates the Aufbau principle. This is because electrons repel each other. It is very highly anti-corrosive properties and used in surface coating. It is used in pigments and stainless steel production.
The largest producers of chromium ore are South Africa, Turkey, India and Kazakhstan.