Sir Humphrey Davy kept the old English name for the newly discovered element, calling it ‘ potash ’, which is short for ‘pot of ash’ – the method previously used to obtain this chemical. This time, he passed the electric current through molten samples of both compounds, which resulted in a metal droplet formed by each substance – a pure elemental form of potassium that was isolated from the potash and a pure sodium metal was isolated from the soda ash. During his second attempt to separate the elements from the potash and soda ash compounds, he decided to leave out the water. Namely, although the electric current indeed freed potassium and sodium from the compound, they instantly reacted with the H 2 O (water) molecules. However, due to the high reactivity of potassium and sodium, the first experiment of the English chemist left no significant results. To that end, Davy attempted electrolysis on both compounds. In 1806, the English chemist Sir Humphry Davy attempted to distinguish these two substances by isolating the compounding elements. The two substances differed only based on the source they were obtained from. They called it soda ash ( sodium carbonate, Na 2 CO 3 ). At the time, people were also familiar with another similar substance that they obtained from a specific type of rock with mineral alkali properties. This is a potassium compound called potassium carbonate (K 2 CO 3 ), which was used as a cleaning agent. Since 500 A.D., people would collect the ashes from burnt wood and wash them in order to obtain potash, also referred to as vegetable alkali. In contact with air, the elemental potassium oxidizes and tarnishes very quickly. However, when it comes into contact with H 2 O (water) molecules, this soft metal reacts violently by releasing hydrogen and emitting a purple flame. This alkali element of the periodic table has an electronegativity of 0.8 according to Pauling, whereas the atomic radius according to van der Waals is 0.235 nm.Īs it has a lower density than water, potassium can actually float on it. Potassium is a soft, silvery-white metal that reaches its boiling point at 759☌ (1398☏ or 1032 K), while the melting point is achieved at 63.5☌ (146.3☏ or 336.7 K). Represented by the symbol K, the chemical element potassium has the atomic number 19, an atomic mass of 39.0983 g.mol -1, and electron configuration 4s 1. The energy of the first ionization: 418.6 kj.mol -1ĭiscovery date: In 1987 by Sir Humphry Davy Half-life: From less than 10 picoseconds to 1.248×109 yearsĮlectronegativity according to Pauling: 0.8 Physical state: A soft metal at room temperature The symbol in the periodic table of elements: K Fact Box Chemical and Physical Properties of Potassium Most notably, it’s responsible for the control and regulation of the exchange of electrical impulses in the heart’s cells and within other muscles, as well as the regulation of the fluid balance within the body. This extremely reactive chemical is also one of the most essential trace minerals found in the human body, and it’s responsible for some vital processes. As a member of the alkali metals family in the periodic table, potassium has one valence electron in its outermost shell. With about 2.0 to 2.5 percent occurrence in the Earth’s crust, it’s the eighth most abundant element found in the layers of our planet. Potassium is a chemical element with the atomic number 19 in the periodic table of elements.
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