Chemistry of Metals and Alloys

Ruby (red due to chromium impurities) and sapphire (blue due to iron/titanium impurities) are both gem varieties of the mineral corundum, which is crystalline aluminum oxide (Al2O3). They are among the hardest gemstones after diamond.

Computer disc does not contain mercury.

Both bismuth and antimony are diamagnetic materials, meaning they are weakly repelled by a magnetic field and do not retain magnetic properties when the external field is removed. Diamagnetic substances have all their electrons paired and no permanent magnetic moment. This property contrasts with paramagnetic and ferromagnetic materials.

Chromium is the key component in heating element alloys like nichrome (nickel-chromium). Pure chromium isn't used alone, but among these options, it's the only element relevant to resistance heating alloys.

Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle.

Heating elements are made of chromium (in the form of nichrome alloy with nickel). Chromium has high electrical resistance and high melting point, making it ideal for converting electrical energy to heat without degrading. Iron would rust, silver is too expensive and has low resistance, and zinc has too low a melting point.

Bronze is primarily an alloy of copper (about 88%) and tin (about 12%). This combination gives bronze its characteristic properties like corrosion resistance and low friction. Copper-zinc makes brass, copper-nickel makes cupronickel, and copper-chromium isn't a standard alloy.

Gold is one of the few metals that occurs naturally in its pure (native) metallic state. This is because gold is relatively unreactive and doesn't easily combine with other elements. Copper, iron, and zinc are usually found as ores (compounds) and require smelting to extract the pure metal.

More reactive metals (like alkali and alkaline earth metals) have a stronger tendency to form compounds because they readily lose electrons to achieve stable electron configurations. Less reactive metals (like gold and platinum) are more stable in their pure form and resist chemical combination. Reactivity is directly related to compound-forming tendency.

Linotype metal alloy contain 86% Pb, 11% Sb and 3% Sn and has been used for over five centuries in printing processes.

A. Copper has very good anticorrosive property and is used for making wires used in electrical industry and for water and steam pipes. B. German silver contains Cu 25-30%, Zn 25-30% and Ni 40–50%. C. Zinc dust is used as a reducing agent in the manufacture of dye-stuffs, paints, etc., and in several organic and inorganic synthesis reactions.

24 carat gold is 99.9% pure gold. The carat system measures purity in 1/24 parts - so 24 carats means 24 out of 24 parts are pure gold. Lower carats like 22K contain other metals like copper or silver for durability.

German silver (also called nickel silver) is an alloy of copper (50-70%), zinc (15-30%), and nickel (5-30%). Despite the name, it contains NO silver. The name comes from its silver-like appearance. It's corrosion-resistant and used in utensils, musical instruments, and jewelry.