Chemistry - Metals

Introduction

• The material (which could be an element, compound, or alloy) that is characteristically hard, shiny, opaque, and has the property to conduct heat and electricity, is known as metal.

• Metals are naturally found in the earth’s crust in impure form i.e. ores. And, it is extracted through mining process.

• Among all known 118 elements (of the periodic table), about 91 elements are metals.

Features of Metals

• Following are the significant features of metals −

  • Metals are generally malleable - it means, its shape can be changed permanently without breaking and cracking.

  • Metals are fusible – it means; it can be fused or melted easily.

  • Metals are ductile – it means; it can be given any shape even a thin sheet or wire.

  • Metals are good conductor of heat and electricity; heaver, lead is an exception, as it does not carry electricity.

  • Metals naturally react with various non-metals and forms compounds. Metals can react with bases and acids. E.g. 4 Na + O₂ → 2 Na₂O (sodium oxide), etc.

Alloys

• An alloy is a product of the mixture of two or more elements in which metal dominates.

• In order to produce or manufacture a desirable product, different metals (in different ratios) are mixed (i.e. alloys). E.g. alloys of iron namely stainless steel, cast iron, alloy sheet, etc. contribute a large proportion of both by quantity and commercial value.

• Metals are usually made alloys with the purpose to make it more resistant to corrosion, less brittle, to give attractive colors, etc.

Metal Terminologies

• Base Metal − In chemistry, the meaning of base metal is – the metal that can be easily oxidized or corroded as well as reacts easily with HCl (dilute hydrochloric acid) and forms hydrogen. E.g. iron, nickel, zinc, lead, etc.

• Ferrous Metal − "Ferrous" is a Latin word, which means the substance "containing iron." E.g. steel, etc.

• Heavy Metal − The metal which are much denser than the normal metal is categorized as heavy metal. The heavy metals are toxic or poisonous at low concentrations. E.g. mercury (Hg), arsenic (As), chromium (Cr), cadmium (Cd), thallium (Tl), and lead (Pb).

• Precious Metal − The metallic elements, which have rare metallic chemical element of high economic value, is categorized as precious metal. E.g. platinum, gold, silver, palladium, etc.

• Noble Metal − The metals that are resistant to corrosion or oxidation. E.g. ruthenium (Ru), rhodium (Rh), palladium (Pd), etc.

Application of Metals

• Following are the significant applications of the metals −

  • As metals are good conductor of heat and electricity; therefore, it is used as electric wire and in many other electric appliances including electric motors, etc. E.g. copper, silver, aluminum, etc.

  • Heavy metals are being used in the constructions of bridge, pool, and for many such purposes.

  • Many metals are used to manufacture various home items, such as, utensils, pots, stoves, etc.

  • Metals are frequently used to manufacture many types of tools ranging from a simple screw driver to a heavy rod roller.

  • Precious metals have beautiful look and they are attractive (e.g. gold, silver, etc.); therefore, they are used as ornaments.

  • Some specific metal is used for heat sinks that protects the sensitive equipment from overheating.

  • Radioactive metals (e.g. uranium and plutonium) are used in the generation of nuclear energy.

  • Mercury is a metal that remains in liquid form at room temperature; it is used in thermometer.