Potassium is a chemical element with symbol K (derived from Neo-Latin, kalium) and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name is derived. In the Periodic table, potassium is one of seven elements in column (group) 1 (alkali metals):they all have a single valence electron in their outer electron shell, which they readily give up to create an atom with a positive charge - a cation, and combine with anions to form salts.
Alkali metals are highly reactive, soft, silver, and shiny metals found in Group 1. They readily lose their outermost electron to form positive ions (cations) with a charge of +1.
Potassium melts at 336.7 K and boils at 1032 K.
The number of protons in the nucleus, which defines the element.
The average mass of an atom, including protons and neutrons.
A measure of how strongly an atom attracts electrons in a bond.
The energy required to remove an electron from an atom.
The arrangement of electrons in the atom's energy shells.