Chromium 

The atomic number of an element is the number of protons in an atom. This number is usually found in the top right hand corner of the symbol. The atomic number for Chromium is 24. This means Chromium has 24 protons per atom. 

The atomic mass is the number of protons plus the number of neutrons per atom. The atomic mass of Chromium is 51.996 (24 protons + 27.996 neutrons)

• Chromium has been used to coat the inside of gun barrels because it's able to withstand the hot powder gases. 
• The red colour of rubies is produced by a small amount of Chromium 

Chromium is commonly used to plate brass    Above is a picture of Chromium in its natural form.

and steel objects.    

Stainless steel contains 12-18% Chromium.   

• Chromium has been used to coat the inside of gun barrels because it's able to withstand the hot powder gases. 
• The red colour of rubies is produced by a small amount of Chromium
• Chromium Oxide prevents corrosion 
• Chromium is very toxic so Chromium salts are used to preserve wood
• Chromium salts are used for the tanning of leather. The Chromium stabilizes the leather by cross linking the fibres. 

                                                                             Chromium is used in paint. Such as Chromium yellow used on school buses.

• Chromium was discovered in France in the late 1790s, it took until the 1960s before it was recognized as being an important element.
• Chromium has a high melting point, which is 1830°C
• Chromium is odorless, tasteless, and malleable (able to be hammered or pressed permanently out of shape without breaking or cracking.) 
• The name of the element is derived from the Greek word "chrōma" , meaning colour, because many of its compounds are intensely coloured.

http://hyperphysics.phy-astr.gsu.edu/hbase/pertab/cr.html

http://en.wikipedia.org/wiki/Chromium

picture of chromium- http://www.santjuliadecerdanyola.net/wp-content/uploads/2011/08/Chromium.png