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Oxidation & Electrons | Appearance & Characteristics Reactions | Compounds | Radius | Conductivity Abundance & Isotopes 
Batteries - zinc acting as both electrode and container |
General:
| Name: Zinc | Symbol: Zn |
| Type: Transition Metal | Atomic weight: 65.38 |
| Density @ 293 K: 7.14 g/cm3 | Atomic volume: 9.2 cm3/mol |
| Discovered: Zinc ores have been used for making brass (a mixture of copper and zinc) and other alloys since ancient times. A zinc alloy comprising 87.5% zinc was discovered in an ancient site in Transylvania. Zinc smelting began in the 12th century in India by reducing calamine (zinc carbonate, ZnCO3) with wool and other organic materials. | |
States
| State (s, l, g): solid | |
| Melting point: 692.68 K (419.53 oC) | Boiling point: 1183 K (910 oC) |
Energies
| Specific heat capacity: 0.39 J g-1 K-1 | Heat of atomization: 131 kJ mol-1 |
| Heat of fusion: 7.322 kJ mol-1 | Heat of vaporization: 115.30 kJ mol-1 |
| 1st ionization energy: 906.4 kJ mol-1 | 2nd ionization energy: 1733.2 kJ mol-1 |
| 3rd ionization energy: 3832.6 kJ mol-1 | Electron affinity: kJ mol-1 |
Oxidation & Electrons
| Shells: 2,8,18,2 | Electron configuration: [Ar] 3d10 4s2 |
| Minimum oxidation number: 0 | Maximum oxidation number: 2 |
| Min. common oxidation no.: 0 | Max. common oxidation no.: 2 |
| Electronegativity (Pauling Scale): 1.65 | Polarizability volume: 6.4 Å3 |
Appearance & Characteristics
| Structure: hcp: hexagonal close packed | Color: bluish silver |
| Hardness: 2.5 mohs | |
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Harmful effects:
Zinc is not considered to be particularly toxic. Zinc is essential for good health, but excess zinc is toxic and can cause nausea. Characteristics: Zinc is a bluish-silver, lustrous metal that tarnishes in moist air, producing a layer of carbonate. It is somewhat brittle at room temperature but malleable above 100 oC. Zinc reacts with both acids and alkalis. It is a fair conductor of electricity, and burns in air with a bright bluish-green flame producing white clouds of the oxide. Uses: Zinc is used to galvanize iron to inhibit corrosion. Zinc forms many alloys with other metals such as brass, German silver, nickel silver, typewriter metal and solders. Zinc alloys are used in die-castings for the car industry. The metal acts as both the container and as an electrode in zinc-carbon batteries. The drawback of this dual use is that the electrode is consumed when the battery is in use, getting thinner until eventually the battery starts leaking. Zinc is an essential trace element for animals and plants. |
Reactions
| Reaction with air: vigorous, ⇒ ZnO | Reaction with 6 M HCl: mild, ⇒ H2, ZnCl2 |
| Reaction with 3 M HNO3: vigorous, ⇒ Zn(NO3)2, NOx | Reaction with 6 M NaOH: mild, ⇒ [Zn(OH4)]2-, H2 |
Compounds
| Oxide(s): ZnO, ZnO2 (zinc peroxide) | Chloride(s): ZnCl2 |
| Hydride(s): ZnH2 |
Radius
| Atomic radius: 135 pm | Ionic radius (1+ ion): pm |
| Ionic radius (2+ ion): 88 pm | Ionic radius (3+ ion): pm |
| Ionic radius (2- ion): pm | Ionic radius (1- ion): pm |
Conductivity
| Thermal conductivity: 116 W m-1 K-1 | Electrical conductivity: 0.169 x 106 S cm-1 |
Abundance & Isotopes
| Abundance earth's crust: 70 parts per million by weight, 22 parts per million by moles | |
| Abundance solar system: 2 part per million by weight, 30 parts per billion by moles | |
| Cost, pure: $3.7 per 100g | |
| Cost, bulk: $0.12 per 100g | |
| Source: Zinc is found in nature combined with other elements as ores. The main ores of zinc are sphalerite (sulfide), smithsonite (carbonate), hemimorphite (silicate), and franklinite (zinc, manganese, iron oxide). Commercially, zinc is obtained from zinc sulfide minerals. The minerals are concentrated and then usually roasted to oxidize the zinc sulfide to zinc oxide. Zinc is then extracted by either large-scale electroplating (electrowinning) or by pyrometallurgy, where processing reduces zinc oxide with carbon or carbon monoxide at 950 oC into the metal. | |
| Isotopes: Zinc has 25 isotopes whose half-lives are known, with mass numbers 57 to 83. Of these, four are stable, 64Zn, 66Zn, 67Zn and 68Zn. Over 48.6% of of naturally occurring zinc is in the form of 64Zn. | |
