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Chemical element with atomic number 30 (Zn) From Wikipedia, the free encyclopedia
Zinc is a chemical element with the symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size.[b] Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity (electrowinning).
Zinc | |||||||||||||||
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Appearance | silver-gray | ||||||||||||||
Standard atomic weight Ar°(Zn) | |||||||||||||||
Zinc in the periodic table | |||||||||||||||
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Atomic number (Z) | 30 | ||||||||||||||
Group | group 12 | ||||||||||||||
Period | period 4 | ||||||||||||||
Block | d-block | ||||||||||||||
Electron configuration | [Ar] 3d10 4s2 | ||||||||||||||
Electrons per shell | 2, 8, 18, 2 | ||||||||||||||
Physical properties | |||||||||||||||
Phase at STP | solid | ||||||||||||||
Melting point | 692.68 K (419.53 °C, 787.15 °F) | ||||||||||||||
Boiling point | 1180 K (907 °C, 1665 °F) | ||||||||||||||
Density (at 20° C) | 7.140 g/cm3 [3] | ||||||||||||||
when liquid (at m.p.) | 6.57 g/cm3 | ||||||||||||||
Heat of fusion | 7.32 kJ/mol | ||||||||||||||
Heat of vaporization | 115 kJ/mol | ||||||||||||||
Molar heat capacity | 25.470 J/(mol·K) | ||||||||||||||
Vapor pressure
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Atomic properties | |||||||||||||||
Oxidation states | common: +2 −2,[4] 0,? +1[5] | ||||||||||||||
Electronegativity | Pauling scale: 1.65 | ||||||||||||||
Ionization energies |
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Atomic radius | empirical: 134 pm | ||||||||||||||
Covalent radius | 122±4 pm | ||||||||||||||
Van der Waals radius | 139 pm | ||||||||||||||
Spectral lines of zinc | |||||||||||||||
Other properties | |||||||||||||||
Natural occurrence | primordial | ||||||||||||||
Crystal structure | hexagonal close-packed (hcp) (hP2) | ||||||||||||||
Lattice constants | a = 266.46 pm c = 494.55 pm (at 20 °C)[3] | ||||||||||||||
Thermal expansion | 30.08×10−6/K (at 20 °C)[a] | ||||||||||||||
Thermal conductivity | 116 W/(m⋅K) | ||||||||||||||
Electrical resistivity | 59.0 nΩ⋅m (at 20 °C) | ||||||||||||||
Magnetic ordering | diamagnetic | ||||||||||||||
Molar magnetic susceptibility | −11.4×10−6 cm3/mol (298 K)[6] | ||||||||||||||
Young's modulus | 108 GPa | ||||||||||||||
Shear modulus | 43 GPa | ||||||||||||||
Bulk modulus | 70 GPa | ||||||||||||||
Speed of sound thin rod | 3850 m/s (at r.t.) (rolled) | ||||||||||||||
Poisson ratio | 0.25 | ||||||||||||||
Mohs hardness | 2.5 | ||||||||||||||
Brinell hardness | 327–412 MPa | ||||||||||||||
CAS Number | 7440-66-6 | ||||||||||||||
History | |||||||||||||||
Discovery | Indian metallurgists (before 1000 BCE) | ||||||||||||||
First isolation | Andreas Sigismund Marggraf (1746) | ||||||||||||||
Recognized as a unique metal by | Rasaratna Samuccaya (1300) | ||||||||||||||
Isotopes of zinc |