Name       : Potassium 
Symbol     : K
Atomic #   : 19
Atom weight: 39.0983
Melting P. : 63.25
Boiling P. : 759.9
Oxidation  : -1
Pronounced : pe-TASS-i-em
From       : English pot ash. Symbol from Latin kalium, "alkali"
Identified : Sir Humphry Davy in 1807
Appearance : Soft, waxy, silvery-white metal
Note       : Catches fire spontaneously upon contact with water

[Properties]

  Pure potassium metal is so soft that many who have worked with it refer
to it as a waxy substance. Few people have had such an opportunity,
however, because potassium is highly unstable in the normal human
environment. It reacts with the oxygen in dry air to produce the potassium
superoxide. If there is any moisture in that air, or if the sample of
potassium comes into direct contact with water, you get potassium hydroxide
(KOH) and hydrogen gas.  The reaction is exothermic; that is, it generates
heat - enough heat in this case to ignite the hydrogen gas.
  Potassium belongs to Group IA on the periodic chart. With the notable
exception of hydrogen (H), the elements in this group are all highly
reactive metals that cannot exist in the elemental forms in nature. These
metals are commonly called the alkali metals, due to the fact they all form
such strong, caustic (alkaline) hydroxides. Household lye, for example, is
made up of sodium hydroxide, potassium hydroxide, or a mixture of the two.
  Potassium and its salts impart a violet color to a flame test.
