P.4 11/5/14
What’s the Atomic Mass? Is it A
Metal?
39 amu, and potassium is in group 1 so it is an Alkaline Metal.
What group and period does it belong in?
Potassium belongs in group number 1 and period number 4.
Isotopes
There are three naturally occurring isotopes of potassium, potassium39,potassium-40, and potassium-41.
Potassium-40 is radioactive, there are about ten artificial radioactive isotopes of potassium. The Relative abundance of isotope
Potassium-39 is 93.3% abundance. And isotope Potassium-41 has a 6.7% relative abundance. The discovery of Potassium
Potassium was discovered by Sir Humphrey
Davy at 1807 in England. Until the 18th century no distinction was made between potassium and sodium. Potassium was isolated in 1807 by
Sir Humphry Davy, who obtained it through the electrolysis of very dry molten caustic potash
(KOH, potassium hydroxide).
Sir Humphry Davy
Potassium’s Melting and Boiling Point
• Boiling Point = 759°C, 1398.2°F, 1032.15 K
• Melting Point = 63.5°C, 146.3°F, 336.65 K
Density and State, under normal conditions
(862 kg m-3 )
Solid
Uses for Potassium
The greatest demand for potassium compounds is in fertilizers. Many other potassium salts are of great importance, including the nitrate, carbonate, chloride, bromide, cyanide and sulfate. Potassium carbonate is used in the manufacture of glass. Potassium hydroxide is used to make detergent and liquid soap.
Potassium chloride is used in pharmaceuticals and saline drips.
K’s Abundance
• Potassium is the seventh most abundant metal in the Earth’s crust. It makes up 2.4% by mass. There are deposits of billions of tonnes of potassium chloride throughout the world. Mining extracts about 35 million tonnes a year.
• Potassium is not an abundant or noticeable element in