1. Transition Metal Manganese 5E Ho Sin Yin(9) 5E Tong Ka Wai(19) 5E Tso Ka Wing (20)

2. What is Manganese? Transition metal Atomic number: 25 No. of protons: 25 No. of neutrons: 30 Relative atomic mass: 54.94 State: solid

3. Electronic diagram Layers of electron shells: 4 (Period4)

4. 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

5. Oxidation state +2: most stable, pale pink color (aq) +4: brown/black color, found in MgO2 +7: purple color, found in MnO 4 - +6: green color

6. Manganese ore Manganese oxide

7. 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

8. 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)

9. 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 )

10. ~The End~