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Sodium

Element, properties, uses, Facts

Sodium Periodic Table Facts

Sodium (Na) is a soft, low melting, silvery-white alkali metal or chemical element of Group 1 or IA of the periodic table. It is extensively involved in our life process and many of its compounds are used from the early days of human civilization. Due to the presence of 3s1 outer electronic configuration, the metal sodium occupies Group-1 or 1A in the periodic table.

Position of alkali metal Sodium on the periodic table elements

The physical and chemical properties of the element readily understand in terms of its simple outer electronic configuration. Some physical and chemical properties like melting point, boiling point, common oxidation number or state, and density given below the table.

Sodium element chemical symbol and the periodic table properties

Properties of sodium
Atomic number 11
Atomic weight 22.989
Melting point 97.79 °C, ​208.03 °F
Boiling point 882.94 °C, ​1621.29 °F
Density 0.968 g/cm3
Molar heat capacity 28.230 J mol-1K-1
Electrical resistivity 47.7 nΩ·m
Atomic radius 186 pm
Covalent radius 166±9 pm
Chemical properties
Oxidation number +1
Electronegativity Pauling scale – 0.93
Ionization energy 1st – 495.8 kJ/mol
2nd – 4562 kJ/mol
3rd – 6910 kJ/mol

Occurrence and Production

Sodium is the seventh most abundant periodic table element and the fifth-most abundant metal after aluminum, iron, calcium, and magnesium. It has occurred 22,700 ppm in the earth’s crust. It has occurred in many minerals like rock salt (NaCl), carbonate (trona), nitrate (saltpeter), borate (borax), etc. The vast deposit of rock salt may be obtained by the evaporation of ancient seas. The Cheshire salt field in the United Kingdom occupies the areas of 60 km × 24 km and a nearly 400-meter thick layer. Similar deposits are present in Saskatchewan, Canada, Carlsbad, New Mexico. Besides the rock salts, natural brines and oceanic waters contain large amounts of sodium chloride.

Plants and animal organism also contains with sodium compounds like NaCl (in animal). Sodium-ion (Na+) constitutes 0.3 percent of human blood, 0.6 percent of bone, and 0.6 to 1.5 percent of human muscles.

Sodium is extracted by the electrolysis of a fused mixture of sodium chloride and calcium chloride. The temperature for electrolysis is considerably lower than the melting point of pure sodium chloride (803°C). Therefore, the difficulties from the volatility of Na (boiling point 883°C) are largely eliminated. Under this condition discharge potential for Na+ ion is lower than that of the Ca+2 ion. Sodium metal is preferentially deposited with 1 to 2 percent of calcium metal in a cylindrical steel cathode. Chlorine liberated by this production process at the central graphite electrode (anode) is collected through the nickel dome.

Properties, Reactivity, and Compounds

All the alkali metals like lithium, sodium, potassium, and rubidium are soft, low melting, silvery-white, metals but cesium is a golden yellow colour. They are normally adopting a body-centered cubic crystal structure but at low temperature, lithium forms a hexagonal closed packed arrangement. Only the one electron in the 3s orbital of the metal atom takes part in metallic chemical bonding. It makes the metal soft and low melting materials. The large difference between the first and second ionization energy of sodium suggests that the preferred oxidation state of the metal will be +1.

The first ionization energy of metal is more than compensated lattice energy suggests that most of the compounds are formed by ionic bonding. Hence major chemistry of the element is dominated by ionic bonding. The reactivity of alkali metals towards water increases from lithium to cesium. Therefore, at 25°C water reacts with lithium slowly, sodium reacts vigorously, potassium reacts with flame, and rubidium and cesium react with the explosion. It burns with air or oxygen to give Na2O2. Sodium reacts with carbon to form acetylides Na2C2. It forms series of crystalline solid salts with different types of anions that are soluble in water.

Sodium reacts directly react with hydrogen when heated to form an ionic hydride containing H ion. All the alkali metals halides are colorless, water-soluble crystalline solids formed by the reaction of MOH or M2CO3 with appropriate HX.

Uses of Sodium

More than half of the sodium produced every year is used as a Na/Pb alloy to manufacture antiknock compounds like lead tetraethyl. The production and manufacture of lead tetraethyl are likely to be decreased due to environmental pollution like lead posing. It is used as a reducing agent in the extraction of titanium and zirconium. Dispersion of sodium in various media like carbon, potassium carbonate is used as a chemical catalyst in various sections of alkenes for the production of artificial rubber.

Sodium is the most favorable material for heat exchange in the fast breeder nuclear power reactor due to its low melting point, low viscosity, and low neutron absorption cross-section with high heat capacity and thermal conductivity. A considerable amount of metal is consumed in the production of various types of sodium compounds like hydroxide (NaOH), peroxide (Na2O2), hydride (NaH), organosodium compounds, etc. Sodium hydroxide is largely used in the manufacture of different types of chemicals like alcohol or phenol, resorcinol, hypochlorite, phosphate, and in the paper, pulp, and rayon industries.