Manganese is a useful hard gray metal. Not a very common element, manganese makes up less than 0.1% of the earth's crust. When it is added to steel, it increases the hardness and strength of the steel.
Black powdered manganese dioxide has wide use as a catalyst and absorbing chemical. It is used in dry cells.
Manganese is included in a group of elements called transition elements. They are classified together because in chemical changes electrons are added to inner rather than outer shells of their atoms.
Manganese (symbol Mn) is element number 25. Its atomic weight is 54.938 (54.94, O= 16).
