Sodium

sodium

The salt we eat every day contains a lot of sodium. Although very abundant on Earth, sodium is never found in its pure form naturally. Thus, it forms compounds with other elements. Sodium chloride, NaCl, which also contains chlorine, is the most common sodium compound. It is also known as the mineral halite, and is what makes seawater salty.
Other sodium minerals include sodalite, a soft blue stone that can be shaped and polished. Pure sodium is soft enough to cut with a knife.

It reacts with oxygen in the air, forming a compound called sodium oxide, and bursts into flames when it comes into contact with water. Sodium compounds in fireworks burn with an orange-yellow color. In ancient Egypt, crystals of sodium compounds were used for the momification process. Another useful compound is sodium bicarbonate, NaHCO3, which when mixed with water releases bubbles of carbon dioxide, CO2. When purified, sodium chloride, or common salt, has several uses. It causes ice to melt, so it is used mixed with sand to keep roads from freezing in winter. This helps thaw them and make them safer. It is also an important seasoning for foods.

Summary of properties (Na)

Atomic weight22.98976928(2)
Discoverer (year)Davy, Humphry (1807)
Natural formmetallic solid (body centered cubic)
Electron configuration[Ne] 3s1
Melting point (ºC)98
Boiling point (ºC)883
Abundance in earth's crust (ppm)23600
Isotope (abundance)23Na (100))
Density g/cm30.97
Van der Waals radius (pm)227
Covalent radius (pm)160
Electronegativity (Pauling)0.93
Vaporization enthalpy (kJ/mol)89.04
Enthalpy of fusion (kJ/mol)2.60
Specific heat capacity (J/g·K) at 25ºC and 1 atm1.23
Thermal conductivity (W/cm·K) at 25ºC and 1 atm1.410
Oxidation state+1
Electron affinity (eV)0.55
1st Ionization potential (eV)5.1391

Back to the Periodic Table of the Elements.