Chemistry B2 Group 11A: Alkaline Earth Metals

B2 Group 11A: The Alkaline Earth Metals

• Alkaline earth metals are bivalent with a charge of 2+.
• React with water to produce hydrogen gas and metal hydroxide: M + H2O → H2 + M(OH)2.
• React with hydrogen to form hydrides: M + H2 → MH2.
• Decomposition of metal hydroxides occurs upon heating: M(OH)2 + HEAT → MO + H2O.
• Hydroxide salts are less soluble in water compared to alkalis.
• Carbonates, sulfates, phosphates, and fluoride salts are generally insoluble in water.

B2.1 Calcium

• Discovered by Sir Humphry Davy through electrolysis.
• Emits a brick-red flame in a non-luminous setting.
• Calcium ion (Ca^2+) is the second most abundant cation in extracellular fluid (ECF).
• Vital for nerve transmission, cardiac function, blood coagulation, and bone structure.
• Key calcium salts include amorphous chalk and crystalline limestone; used extensively in construction.
• Precipitated calcium carbonate serves as both an external dentifrice and internal antacid.
• Ringer's solution, an isotonic chloride solution, contains calcium, sodium, and potassium chlorides.
• Lactated Ringer's solution enhances calcium absorption by including sodium lactate.
• Commonly used calcium supplements.
• Vleminckx solution combines lime and sublimed sulfur, often used for acne treatment.
• Calcium’s effectiveness increases with Vitamin D for absorption enhancement.

B2.2 Strontium

• Isolated by Sir Humphry Davy through electrolysis.
• Occurs naturally in sulfate forms like barite and heavy spar.
• Produces a crimson-red flame in a non-luminous flame.
• Strontium ion is similar to calcium but is less toxic and has a milder effect.

B3 Group 1B: The Coinage Metals

• Coinage metals include copper (Cu), silver (Ag), and gold (Au).
• Recognized for ornamental and currency uses, often termed "noble metals."
• These metals occur in a free state in nature, are chemically inert, and oxidize slowly.
• They exhibit remarkable malleability and ductility.
• Silver has the highest electrical conductivity, followed by copper and gold.
• In terms of thermal conductivity, silver ranks first, gold second, and copper third.
• Possess an oligodynamic effect, showcasing a toxic impact on microbes.

B3.1 Copper

• Deficiency leads to Menke's Disease, while toxicity can cause Wilson's Disease (hepatolenticular degeneration).
• Antidotes for copper toxicity include British Anti-Lewisite (BAL) or dimercaprol, and Penicillamine.
• Common copper alloys include brass (Cu + Zn), bronze (Cu + Sn), German silver (Cu + Zn + Ni), and sterling (Cu + Ag).

B3.2 Silver

• Known as "Argentum" in Latin, silver is a lustrous white metal with the Ag+ ion.
• Acts as a protein precipitant and has antiseptic properties.
• Long-term use can lead to argyria, a condition characterized by skin discoloration.
• Various silver compounds serve as antiseptics and in treatments, such as silver nitrate for newborns and mild silver protein as a gentle astringent.

Applications and Uses of Metals

• Copper compounds are utilized as astringent antiseptics, while calcium compounds act as antacids and in disinfectants.
• Barium sulfate functions as a radiopaque contrast medium for medical imaging.
• Magnesium compounds serve as laxatives and cathartics, particularly magnesium sulfate (Epsom salt).
• For sedimentation, copper and strontium compounds can function as sedatives.
• Silver compounds are utilized for their antiseptic properties in various formulations.
• Barium compounds are used in pyrotechnics and as treatment for certain diseases.