Potassium Potassium Potassium is a chemical element with symbol K (from Neo-Latin "kalium") and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals. All of the alkali metals have a single valence electron in the outer electron shell, which is easily removed to create an ion with a positive charge – a cation, which combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air
19 (number) the Bábí and Bahá'í faiths, a group of 19 is called a "Váhid", a Unity (Arabic: واحد "wāhid", "one"). The numerical value of this word in the Abjad numeral system is 19. 19 (number) 19 (nineteen) is the natural number following 18 and preceding 20. It is a prime number. In English speech, the numbers 19 and 90 are sometimes confused, as they sound very similar. 19 is the 8th prime number. 19 is the seventh Mersenne prime exponent. 19 is the maximum number of fourth powers needed to sum up to any natural number. It is the fourth value