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Oxidation & Electrons | Appearance & Characteristics Reactions | Compounds | Radius | Conductivity Abundance & Isotopes 
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General:
| Name: Magnesium | Symbol: Mg |
| Type: Alkali Earth Metal | Atomic weight: 24.305 |
| Density @ 293 K: 1.738 g/cm3 | Atomic volume: 13.97 cm3/mol |
| Discovered: Joseph Black recognized magnesium as an element in 1755. It was first isolated by Sir Humphrey Davy in Britain in 1808. The name originates from the Greek word Magnesia, a district of Thessaly. | |
States
| State (s, l, g): solid | |
| Melting point: 923 K (650 oC) | Boiling point: 1363 K (1090 oC) |
Energies
| Specific heat capacity: 1.02 J g-1 K-1 | Heat of atomization: 146 kJ mol-1 |
| Heat of fusion: 8.48 kJ mol-1 | Heat of vaporization (sublimation): 127.4 kJ mol-1 |
| 1st ionization energy: 737.7 kJ mol-1 | 2nd ionization energy: 1450.6 kJ mol-1 |
| 3rd ionization energy: 7732.6 kJ mol-1 | Electron affinity: 78 kJ mol-1 |
Oxidation & Electrons
| Shells: 2,8,2 | Electron configuration: [Ne] 3s2 |
| Minimum oxidation number: 0 | Maximum oxidation number: 2 |
| Min. common oxidation no.: 0 | Max. common oxidation no.: 2 |
| Electronegativity (Pauling Scale): 1.31 | Polarizability volume: 10.6 Å3 |
Appearance & Characteristics
| Structure: hcp: hexagonal close packed | Color: silvery-white |
| Harmful effects: Magnesium powder is an explosive hazard. The bright white light plus ultraviolet from burning magnesium can cause permanent eye damage. | Hardness: 2.5 mohs |
| Characteristics: Magnesium is a lightweight, fairly tough metal that tarnishes in air to form a thin oxide coating. The metal reacts with water to produce hydrogen gas. When it burns in air, magnesium produces a brilliant white light. | |
| Uses: Magnesium is used in photography, flares, pyrotechnics and incendiary bombs. With a density of only two-thirds that of aluminum, magnesium alloys are used in aircraft, car engine casings, and missile construction. The metal is widely used in the manufacturing of mobile phones, laptop computers, cameras, and other electronic components. Magnesium hydroxide (milk of magnesia), sulfate (Epsom salts), chloride and citrate are used in medicine. | |
Reactions
| Reaction with air: vigorous, w/ht ⇒ MgO, Mg3N2 | Reaction with 6 M HCl: mild ⇒ H2, MgCl2 |
| Reaction with 15 M HNO3: vigorous ⇒ NOx, Mg(NO3)2 | Reaction with 6 M NaOH: none |
Compounds
| Oxide(s): MgO | Chloride(s): MgCl2 |
| Hydride(s): MgH2 |
Radius
| Atomic radius: 150 pm | Ionic radius (1+ ion): pm |
| Ionic radius (2+ ion): 86 pm | Ionic radius (3+ ion): pm |
| Ionic radius (2- ion): pm | Ionic radius (1- ion): pm |
Conductivity
| Thermal conductivity: 156 W m-1 K-1 | Electrical conductivity: 22.4 x 106 S cm-1 |
Abundance & Isotopes
| Abundance earth's crust: 2.9 % by weight, 2.5 % by moles | |
| Abundance solar system: 700 ppm by weight, 30 ppm by moles | |
| Cost, pure: 3.7 $/100g | |
| Cost, bulk: 0.32 $/100g | |
| Source: Magnesium is obtained commercially by the 'Pidgeon' process. This high temperature method uses silicon as a reducing agent to extract magnesium from minerals such as dolomite (MgCa(CO 3)2) or magnesite (MgCO 3) or saltwater. | |
| Isotopes: Magnesium has 15 isotopes whose half-lives are known with mass ranges from 20 to 34. Of these 3 are stable, 24Mg, 25Mg and 26Mg. Isotope 24Mg is the most abundant (79%). | |
