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Oxidation & Electrons | Appearance & Characteristics Reactions | Compounds | Radius | Conductivity Abundance & Isotopes 
Sodium metal with oxide layer on uncut surfaces. |
General:
| Name: Sodium | Symbol: Na |
| Type: Alkali Metal | Atomic weight: 22.98977 |
| Density @ 293 K: 0.971 g/cm3 | Atomic volume: 23.7 cm3/mol |
Untarnished sodium stored under oil.
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Discovered: Sodium was first isolated in 1807 by Sir Humphry Davy by the electrolysis of molten sodium hydroxide. The chemical symbol for sodium (Na) comes from the Latin word 'natrium' meaning hydrated sodium carbonate. |
States
| State (s, l, g): solid | |
| Melting point: 370.87 K (97.72 oC) | Boiling point: 1156 K (883 oC) |
Energies
| Specific heat capacity: 1.23 J g-1 K-1 | Heat of atomization: 107 kJ mol-1 |
| Heat of fusion: 2.598 kJ mol-1 | Heat of vaporization (sublimation): 96.960 kJ mol-1 |
| 1st ionization energy: 495.8 kJ mol-1 | 2nd ionization energy: 4562.4 kJ mol-1 |
| 3rd ionization energy: 6912.2 kJ mol-1 | Electron affinity: 52.868 kJ mol-1 |
Oxidation & Electrons
| Shells: 2,8,1 | Electron configuration: [Ne] 3s1 |
| Minimum oxidation number: -1 | Maximum oxidation number: 1 |
| Min. common oxidation no.: 0 | Max. common oxidation no.: 1 |
| Electronegativity (Pauling Scale): 0.93 | Polarizability volume: 23.6 Å3 |
Appearance & Characteristics
| Structure: bcc: body-centered cubic | Color: silvery-white |
| Harmful effects: Sodium is considered to be non-toxic. Contact with the skin may, however, cause irritation and burns. | Hardness: 0.5 mohs |
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Characteristics: Sodium is a soft, silvery-white metal. Freshly cut surfaces oxidize rapidly in air to form a dull, oxide coating. Sodium burns in air with a brilliant yellow flame. Sodium floats on water, because its density is lower than water's. It also reacts vigorously with water - violently if more than a small amount of sodium meets water (see video on left) - to produce sodium hydroxide and hydrogen gas. Explosions are seen when the heat generated by the sodium-water reaction ignites the resulting hydrogen gas. Uses: Metallic sodium is used in the manufacture of sodamide and esters, and in the preparation of organic compounds. The metal also may be used to improve the structure of certain alloys, to descale (smooth the surface of) metal, to purify molten metals, and as a heat transfer agent. Sodium vapor lamps are highly efficient in producing light from electricity and are often used for street lighting in cities. Liquid sodium is used to cool nuclear reactors. Sodium chloride (table salt, NaCl) is vital for good nutrition. |
Reactions
| Reaction with air: vigorous, ⇒ Na2O2 | Reaction with 6 M HCl: vigorous, ⇒ H2, NaCl |
| Reaction with 15 M HNO3: vigorous, ⇒ NaNO3, NOx | Reaction with 6 M NaOH: vigorous, ⇒ H2, NaOH |
Compounds
| Oxide(s): Na2O | Chloride(s): NaCl |
| Hydride(s): NaH |
Radius
| Atomic radius: 186 pm | Ionic radius (1+ ion): 116 pm |
| Ionic radius (2+ ion): pm | Ionic radius (3+ ion): pm |
| Ionic radius (2- ion): pm | Ionic radius (1- ion): pm |
Conductivity
| Thermal conductivity: 142 W m-1 K-1 | Electrical conductivity: 0.21 x 106 S cm-1 |
Abundance & Isotopes
| Abundance earth's crust: 2.3 % by weight, 2.1 % by moles | |
| Abundance solar system: 40 ppm by weight, 2 ppm by moles | |
| Cost, pure: 25 $/100g | |
| Cost, bulk: $/100g | |
| Source: Due to its high reactivity, sodium is found in nature only as a compound and never as the free element. Sodium is obtained commercially by electrolysis of molten sodium chloride. | |
| Isotopes: Sodium has 16 isotopes whose half-lives are known, with mass numbers 20 to 35. Of these, only one is stable: 23Na. | |
