Got Calcium?

The next fourth period element is Calcium (Ca - 20). It has a full 4s shell and is looking to share these two electrons to have a stable Argon configuration. Calcium most commonly exists in solution as Ca⁺². It is the fifth most abundant element on Earth, an Alkaline Earth like Magnesium and exists as a dull gray-silver metal. It oxidizes in air to form a coat of Calcium Oxide and reacts with water but not vigorously enough to spontaneously ignite the generated Hydrogen gas. When it does burn, it produces a characteristic brilliant orange-red flame.


Calcium is essential for living organisms, particularly in cell physiology and is a major material used in the mineralization of teeth, bones and shells. In bone, Calcium combines with Phosphate to form Hydroxylapatite with the formula Ca₅(PO₄)₃(OH). The OH group can be replaced by Fluoride, Chloride or Carbonate. Replacement with Fluoride can strengthen the Hydroxylapatite in tooth enamel, thus the use of Fluoride toothpastes. When in solution Calcium has almost no taste, being described as mildly salty or sour. Its solutions are also colorless.

Calcium Carbonate (CaCO₃), one of the most common Calcium salts, is known as lime and is the main component of limestone. It is used medically as an antacid as in Tums®. Calcium Sulfate (CaSO₄) is the main component of Plaster of Paris and blackboard chalk. Both of these Calcium salts can be found in Portland Cement. Calcium hypochlorite (Ca(OCl)₂) is used as a swimming pool disinfectant (solid Pool Chlorine tablets).

The most abundant isotope of Calcium, ⁴⁰Ca, has a nucleus of 20 protons and 20 neutrons. This is the heaviest stable isotope of any element containing an equal number of protons and neutrons.

Calcium salts exposed in surface rock formations of limestone and other minerals are dissolved through the effects of rain and snow runoff (chemical weathering) and Ca²⁺ ions are released into the ocean. Each of these Calcium ions ultimately removes one free CO₂ molecule and stores it in carbonate rocks formed on the ocean floor. This CO₂ will likely be bound up for hundreds of millions of years in these rocks. This weathering of Calcium from surface rocks thus scrubs CO₂ from the ocean and atmosphere, exerting a strong long-term effect on the climate.

In foods Calcium is found in Dairy products such as milk and cheese. It can also be found in nuts and seeds (like almonds and sesame), blackstrap molasses, beans, figs, collard greens, okra, broccoli, and kale as well as fortified products such as orange juice and soy milk. Dietary supplements are available of the Calcium salts Calcium Carbonate, Citrate, Phosphate and Lactate as well as chelated forms. The recommended daily intake of elemental Calcium for adults is 1000mg. Vitamin D is often added to calcium supplements because it indirectly increases Calcium absorption by increasing the synthesis of the intestinal proteins required to transport Calcium into the bloodstream.

In the body, Calcium is a mineral necessary for life. It plays an critical role in building stronger, denser bones early in life and keeping bones strong and healthy later in life. Besides bone, Calcium has other important uses such as neurotransmitter release and muscle contraction. In the electrical conduction system of the heart, calcium replaces Sodium as the mineral that depolarizes the cell, proliferating the action potential and initiating the beating of the heart. Long-term Calcium deficiency can lead to rickets (softening of the bones and deformities such as bowed legs), poor blood clotting and, in case of menopausal women, osteoporosis.

The most well known Calcium containing food is milk. We drink it at birth as our only source of nutrition (breast milk) and many people continue to consume it in one form or another (cow's milk, goat's milk, cheeses) for the rest of their lives. It is so vital to life that God compares knowledge of Him and His Word to mother's milk, essential for our spiritual nutrition.

1 Peter 2:1-3 - "Therefore, rid yourselves of all malice and all deceit, hypocrisy, envy, and slander of every kind. Like newborn babies, crave pure spiritual milk, so that by it you may grow up in your salvation, now that you have tasted that the Lord is good. (NIV)."