Sodium Element Properties and Information
Sodium Element Properties and Information:
Sodium is eleventh element on the periodic table. Elements are arranged in the periodic table on the basis of the atomic number. Atomic number is the number of protons in the nucleus of the atom. Sodium has an atomic number of 11. It is located in the Group 1 and Period 3 of the periodic table of elements. It is denoted by Na. The name is derived from the English word ‘Soda’.
Although sodium compounds like sodium chloride (salt) and sodium carbonate (soda) have been in use since prehistoric times as flavorings and preservatives respectively, sodium metal was first obtained by Humphry Davy in 1807 by exposing sodium hydroxide to strong currents.
Sodium is the sixth most abundant element on earth. It makes up to about 2.6% of earth’s crust. Sodium metal is highly reactive to be found by itself in nature. Sodium chloride is the most common form in which sodium is available on earth. Sodium chloride is found in many minerals and at the areas where the water bodies have dried up.
Physical Properties:
- Sodium is soft metal at standard temperature and pressure which is silvery in colour if kept in inert environment.
- The atomic mass of sodium is 22.989
- The melting point of sodium is 97.5°C
- The boiling point of sodium is 883°C
- The density of sodium is 970 in S.I. units at 20°C
- Sodium is one of the three elements which can float on water due to their low density. The other metals are lithium and potassium.
- When sodium is subjected to a elevated pressures, its allotropes are formed which are primarily used as insulators. At 1.5 Mbar its colour changes from silver to black. At 1.9 Mbar its colour changes to transparent-red. At 3 Mbar it becomes a clear and transparent solid.
- Among the twenty known isotopes of sodium, only sodium-23 is stable.
Chemical Properties:
- When the sodium is exposed to oxygen in air oxide coatings form on the surface of sodium and immediately turn the surface from silver to greyish black colour.
- Sodium does not react with nitrogen in air even at elevated conditions.
- Sodium reacts vigorously with water. It produces sodium hydroxide and hydrogen gas.
- Most of the soaps are sodium salts of fatty acids.
- Sodium can form water soluble compounds such as halides, nitrates, carbonates and carboxylates.
- Sodium forms intermetallic compounds by forming alloys with other metals such as potassium, calcium and lead.
Methods of Production:
- Electrolysis: The current method used to produce sodium globally is by electrolysis of molten sodium chloride. The electrolysis is carried out in a down’s cell and sodium chloride is mixed with calcium chloride to lower it’s melting point from 883°C to 700°C. As calcium is less electropositive than sodium it does not get deposited at cathode.
- Reduction: Carbothermal reduction of sodium carbonate was the first commercially used method in 19th century in order to produce sodium. The reduction was carried out at 1100°C.
Relevance in Chemical and Related Industries:
- Chemical industries: The metallic sodium is mainly used for the production of sodium azide, sodium borohydride, indigo and triphenylphosphine.
Relevance in Other Industries:
- Nuclear industries: Liquid sodium has a high thermal conductivity and low neutron absorption cross section required to achieve a high neutron flux in the reactor. Thus it is used as a heat transfer fluid in some types of nuclear reactors. The high boiling point of the liquid sodium allows the reactor to operate at normal pressure. Its disadvantages are its opacity which hinders visual maintenance and also its explosive properties.
Health Effects on Exposure:
- Contact: When sodium contacts with water, it forms sodium hydroxide. Contact with the sodium hydroxide on skin, eyes or ingestion can lead to severe burns, in milder cases it causes irritation.
- Over Consumption: Sodium is a compound which is present in many food stuffs and is required to be present in the body in a certain range for optimum functioning of the nerve and muscles but if the concentration increases then it has the potential to damage kidneys and increase the chances of high blood pressure.
Effects on Surroundings:
- Flammable: Powdered sodium is highly flammable. When sodium reacts with water it forms hydrogen gas which is also very flammable.
- Contamination: The sodium metal by itself is not very mobile but if combined with water it forms sodium hydroxide which easily gets leached into the soil. It can contaminate the underground water sources.
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