Potassium Element Number 19  K

Here is quite a bit of Potassium under oil It is very rare I open the jar, as Potassium is a dangerous fire and eplosion hazerd.

 Pure Potassium with oil coating. This metal is very soft, and kinda unattractive. The explosion of Potassium metal is bigger than Sodium when tossed into a bucket of water.

K 19 metal  AW:39.0983, MP:146f,  BP:1398, D.862

Mohs: 0.4

Potassium is a very reactive metal in the alkali group located under Sodium. Like Sodium is reacts violently with water, far more so than Sodium. Potassium is represented on the Periodic Table as K, and after Lithium it is the 2nd least dense metal.

Potassium is important to all life, it has a role in cell structure. Potassium is as abundant in the body as Sulfur, over 100grams in an average person!!! of course this is not pure metal!! Potassium supplements are made to help people maintain Potassium levels.

Potassium is found in many foods, and is sometimes used in a salt alternative, the K40 isotope is used to form the KCI salt substitute. Many claims of the radioactivity of these salt are made. I personally haven't remembered to buy some to test my self. the average claim is approx 86 CPM of beta emission.

K40 is used to date rocks, its half life is quite long, and it will either beta decay to Ca40 or decay to Ar40 through positron emission or electron capture.Very interesting element, it will dissolve in ammonia, and it will burn a very pretty color. My sample actually has a nice tint to the surface of the metal.

 

Calcium Element Number 20 C

 

Calcite with Fuorite cubes 

Calcium is a reactive metal in the earth alkaline group under Magnesium. Calcium is not found in pure metal form in nature because of its reactivity. It is a soft grey metal and  will liberate Hydrogen from water, but not in a very exciting manner. Calcium ranks 5th in abundance in the earths crust.

Calcium is important for animals, it forms teeth and bones. Diatoms have exoskeletons that form chalk when fossilized. The oceans are laced with dissolved Calcium and Diatoms flourish in this water, feeding many other ocean animals.

Calcium is found in nature in compounds such as Calcium Carbonate, or  lime. and it is used in cement and plaster. Caves have Calcium formations, and Calcium is an ingredient in seashells.

Calcium can be used in insecticides and rodentcides, fireworks, flares, antacids, dietary supplements, ice melter, lighting (mine helmets) fertilizer, toothpaste and lots O stuff. Calcium Ions are part of the stuff that makes water "hard".

Most people never think of calcium as a metal, but usually think of milk. It can be interesting to watch in water, and when done reacting leaves behind the white powder we would most likely expect. Calcium  can also  be ignited, the metal will produce a beautiful flame, which is dangerous as well!

Small Calcium metal pieces with minor oxide coating. These tiny pieces are pure metallic form, and these will react in water.

Ca 20 Metal  AW:40.078,  MP:1548,  BP:2703,  D:1.55,  Mohs:1.75