Science and Technology for UPSC Examinations [Chemistry] Part 10- Notes on Alkaline Earth metals

Group 2 of the periodic table is known as Alkaline earth metals and it includes the Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba) and Radium (Ra).

• Beryllium has very low absorption for X-rays and its most important applications are in radiation windows for X-ray tubes.
• Magnesium ions are essential to all living cells, where they play a major role in manipulating important biological polyphosphate compounds like ATP, DNA, and RNA. Hundreds of enzymes thus require magnesium ions to function.
• Magnesium is also the metallic ion at the center of chlorophyll, and is thus a common additive to fertilizers.
• Magnesium hydroxide is an inorganic compound with the chemical formula Mg(OH)2. As a suspension in water, it is often called milk of magnesia because of its milk-like appearance it is used as an antacid and laxative.
• Magnesium has three stable isotopes: 24Mg, 25Mg and 26Mg, all are in significant amount.
• Magnesium is the third most commonly used structural metal. The two most commonly used are iron and aluminum.
• It has a low weight and used in Electronic devices.
• Calcium has four stable isotopes (40Ca and 42Ca through 44Ca).
• New Rocks: The uplift of mountains exposes Ca-bearing rocks to chemical weathering and releases Ca2+ into surface water. This Ca2+ eventually is transported to the ocean where it reacts with dissolved CO2 to form limestone. Some of this limestone settles to the sea floor where it is incorporated into new rocks.
• Dissolved CO2, along with carbonate and bicarbonate ions, are referred to as Dissolved Inorganic Carbon (DIC).
• Making of cheese, where calcium ions influence the activity of rennin in bringing about the coagulation of milk.
• Calcium plays an important role in building stronger, denser bones early in life and keeping bones strong and healthy later in life.
• Approximately ninety-nine percent of the body’s calcium is stored in the bones and teeth.
• Vitamin D is added to some calcium supplements. Proper vitamin D status is important because vitamin D is converted to a hormone in the body which then induces the synthesis of intestinal proteins responsible for calcium absorption.
• Strontium is named after a village in Scotland where it was first discovered.
• The 90Sr isotope is present in radioactive fallout and has a half-life of 28.90 years
• Barium sulfate is used for its heaviness, insolubility, and X-ray opacity.
• 133Ba, is routinely used as a standard source in the calibration of gamma-ray detectors in nuclear physics studies
• Barium sulfate is used as a radio contrast agent for X-ray imaging of the digestive system (“barium meals)
• The most stable isotope of radium is 226Ra, has a half-life of 1601 years and decays into radon gas.
• Radium is over one million times more radioactive than the same mass of uranium, Handling of radium has been blamed for Marie Curie’s death due to aplastic anaemia.