Calcium is a soft, silvery-white metal, but it does not occur naturally in pure form. However, because it forms compounds with many other elements, it is the fifth most abundant element in Earth’s crust, and its compounds are among the most important substances on Earth. Most calcium compounds are white solids, often called limes. Among the most familiar calcium compounds are drawing chalks, white chalk cliffs, porcelain, teeth, cement, seashells, plaster casts on broken limbs and the white scale (limescale) found on faucets and inside kettles.
On the other hand, potassium is one of the most common elements in the Earth’s crust, but we are unlikely to find it as an element in nature. This soft, silvery-white metal is so reactive that it almost always exists combined with other elements as compounds. All living things, from plants to people-need potassium to stay healthy. Potassium compounds have many other important uses. They help matches burn and give fireworks their bright, colourful explosions. They are also found in breathing apparatuses, cotton dyes, liquid soaps, photographic chemicals, etc.
Role of Potassium in Digestion
Potassium electrolytes play an important role in the digestion or breaking down of the food we eat. These electrolytes allow the muscles in our intestines to contract, which is how food is digested. Without effective digestion, our bodies would not get the needed nutrients from food. It would also be impossible to pass waste products through our systems. When we chew food, our mouths add saliva or spit to the food. This saliva contains sodium, potassium and chloride electrolytes. These electrolytes help to soften the food so that it is easier to swallow.
Once food reaches the stomach, potassium ions really start working. The stomach contains a fluid that aids in digesting food. A pump similar to the sodium-potassium pump called the potassium-ion pump removes potassium ions from the digestive fluid. The pump replaces potassium ions with hydrogen ions, which, along with the chlorine ions, create hydrochloric acid (HCI). Hydrochloric acid, also called stomach acid, is a strong acid that can be used to remove rust from steel. This acid does not normally hurt our stomachs because they are coated with thick, bicarbonate-rich mucus. The mucus forms a protective layer around the stomach wall. This ensures that the hydrochloric acid won’t harm the stomach wall by itself when combined with bicarbonate.
Calcium in Periodic Table
Like all elements, calcium is made up of tiny particles called atoms. Calcium has an atomic number of 20. The calcium atom has 20 electrons, which revolve around the nucleus in four shells. There are two electrons in the inner shell, eight in both the second and third shells and two in the outer shell.
Calcium oxide is known as quicklime. It gets the name “quick” because when water is dripped on it, it seems to contort and swell. The calcium formula for calcium hydroxide is Ca(OH)2, also known as “slaked lime”, perhaps because it is used in the garden to “slake” the plant’s “thirst” for lime in acid soils. When the water is squeezed or evaporated out of calcium compounds, the slime can turn into hard cement. In the case of calcium carbonate, hard rocks such as chalk and limestone are formed.
Calcium, along with five other similar elements, including magnesium, is known as an alkaline-earth metal. Together, these six elements make up Group II of the periodic table of elements. Each of these alkaline-earth metals has two electrons in the outermost shell of its atom, and this explains why they all have similar chemical properties.