Sodium is the element that is atomic number 11 on the periodic table. It is located in the alkali metals group on the far left side of the periodic table. The pure element is a bright, silver-colored metal at room temperature and pressure.
Atomic Number 11 Element Facts
- Sodium is an element that clearly illustrates the difference between a pure element and its compounds. Pure sodium burns in water, yet when it combines with chlorine to form table salt it becomes an ionic compound that dissolves in water and is essential for life.
- Each atom of atomic number 11 has 11 protons, which define it as sodium. The symbol for sodium is Na. The symbol comes from the Latin word natrium, which was an old word for salt.
- Only one of the 20 known isotopes of sodium is stable. This is sodium-23. Natural sodium consists entirely of the stable isotope.
- Sodium is the 6th most abundant element in the Earth’s crust.
- Sodium metal quickly tarnishes in air to form a white coating of sodium carbonate and sodium hydroxide. However, powdered sodium will spontaneously ignite when exposed to oxygen.
- Sodium forms numerous important compounds, including sodium chloride, sodium carbonate, sodium hydroxide, and sodium bicarbonate. Sodium chloride (NaCl) is the most abundant sodium compound.
- Sodium compounds have been known and valued since ancient times. Its compounds have been used for medicine, trade, food, and currency. However, the pure metal is so reactive it is not found in nature. Sir Humphry Davy was the first to isolate atomic number 11 in 1807. He used electrolysis of caustic soda to produce sodium. In his lab notebook, he called the new element sodagen.
- The pure metal is so soft it can be cut with a knife. It is also extremely malleable.
- The density of sodium is low enough that the metal floats on water.
- The yellow color of the sun comes mainly from the D line of the sodium spectrum. Sodium burns bright yellow in the flame test, too.
- Sodium uses are endless. The element is used in cells to maintain fluid balance. The ion is used in the electric potential that transmits nerve cell impulses. Sodium compounds are used in alloys, glass, cooking, street lights, heat transfer, prepare inorganic and organic compounds, and really just about any industry you can name.
- Grains of kosher salt contain about half the amount of sodium found in regular table salt.
- Although sodium and the closely related metal potassium are both solids at room temperature, they form an NaK alloy that is a liquid.
- Sodium is produced in massive stars, mainly when a proton is added to the element neon.
- Although sodium metal is not inherently toxic, it is so reactive skin contact with the pure metal causes burns.