Fun Facts about Potassium
Potassium, while seldom encountered in its pure form, is one of the more common elements of the periodic table. Its symbol is K and its atomic number 19, meaning that the nucleus of a potassium atom contains 19 protons. It is found in the leftmost column of the periodic table and is thus classified as a member of group 1, the alkali metals. Like the other members of this group, elemental potassium takes the form of a soft, silvery-white metal and is highly reactive with both water and air. It is so soft that it can easily be cut with a knife; the only metal softer is Lithium, another member of group 1. Because of its high reactivity, pure potassium does not occur naturally. It is found as a variety of ionic salts. It only has one more electron than the noble gas argon, which means that a potassium atom easily sheds that single electron to form a positive ion. Negative potassium ions are much rarer, but they do occur.
1. Potassium has a misleading symbol - an element's symbol usually gives some clue to its name, but the letter K is not found in the word at all. So where does it come from? It comes from the Latin word "kalium," but this name is rarely, if ever, used. The familiar name comes from the word "potash," which sheds some light on how potassium was obtained in past centuries. Potassium occurs in substantial amounts in many plants, but it must be extracted in some manner. The ashes of burnt wood and leaves can be soaked in water until the soluble potassium salts leach out; the resulting solution would then be evaporated, leaving behind potash. This stuff consists mainly of various potassium compounds and can be used for a variety of applications.
2. Potassium is so similar to Sodium that early chemists viewed them as one and the same. Potassium chloride (KCl) is sometimes used as a replacement for table salt (NaCl) by people who need to reduce sodium consumption. It is considerably less tasty than regular salt, however.
3. Potassium is dangerous, at least in its pure form. It reacts violently when exposed to water, releasing pure hydrogen that is easily ignited by the heat of the reaction. It can even ignite when exposed to water vapor in air. For this reason, it must be stored in an inert atmosphere or under mineral oil. To make matters worse, a potassium fire cannot be extinguished with water. That will just add to the blaze. The fire must be controlled with something that will deprive the reaction of oxygen, such as a class D fire extinguisher.
4. Potassium is essential to your health. The human body is roughly .2% potassium, and while this number may seem negligible, that makes K one of the ten most common elements in the body. It is an electrolyte and as such is very important to nerve function. It is vital to every cell in your body, actually, and plays a big part in muscle development and use. The presence of too much potassium results in a condition called hyperkalemia; too little is known as hypokalemia. Neither one is a good thing, of course. Balance is essential.
5. Luckily, it is easy to get enough potassium in your diet. It is present in many common foods. Most K deficiencies result from some existing medical condition rather than a dietary issue, so don't take potassium supplements unless instructed by a physician. Dairy products and most meats contain significant amounts, especially red meat, chicken, and salmon. Many plant foods are even richer in potassium, including bananas, parsley, broccoli, citrus fruits, and nuts.
6. Potassium is also essential to plants. About 95% of the potassium extracted from the earth is used as fertilizer for agricultural applications.