Transition MetalManganese

5E Ho Sin Yin(9) 5E Tong Ka Wai(19) 5E Tso Ka Wing (20)

What is Manganese?

• Transition metal• Atomic number: 25• No. of protons: 25• No. of neutrons: 30• Relative atomic mass: 54.94• State: solid

Electronic diagram

• Layers of electron shells: 4 (Period4)

Characteristics

• Color: silver-gray• Chemically active• Hard, very brittle• Hard to melt, but easily oxidized• Reactive when pure• Powder: Burn in oxygen Reacts with water (rusts like iron) Dissolves in dilute acids

Oxidation state

• +2: most stable, pale pink color (aq) • +4: brown/black color, found in MgO2 • +7: purple color, found in MnO4

-

• +6: green color

Manganese ore Manganese oxide

Applications• Iron and steel production• Key component of low-cost stainless steel • Key component of certain aluminum alloys• Decolorize glass• make violet colored glass• Manganese dioxide: catalyst (催化劑 )• Manganese oxide and manganese carbonate:

fertilizers and ceramics (製陶業 ), making manganese compounds materials

Importance

• Used extensively to produce a variety of important alloys. E.g. soft drinks cans (improve stiffness (堅硬度 ) and corrosion resistance)

• Human body: Manganese-containing enzymes to metabolize carbohydrates, cholesterol, and amino acids. (氨基酸 )

• Human contains 10 - 20 mg manganese. (1/4 in bone, the rest evenly distributed through our tissues)

Humans lack of Manganese?

Health Effects:• Fatness• Blood clotting (血凝結 )

• Skin problems

• Skeleton disorders (骨骼疾病 ) • Birth defects (缺陷 )

• Changes of hair color• Neurological symptoms (精神病 )

~The End~