The importance of metals in human life is pretty self-evident by the names used to describe the ages in ancient literature, e.g., the Iron Age, the Bronze Age, the Copper Age, etc. Although it may go widely unnoticed today, our modern lives are dependent on metals to quite an extent. The discovery of metals paved the way for industrialization to which we owe the modern world we live in today. In fact, some suggest that if metals were discovered much earlier, we’d probably be a Type 1 civilization in the Kardashev scale by now. Out of 118 elements in the periodic table, 92 are classified as metals based on periodicity in their properties such as high melting points, good conductors of electricity, good conductors of heat, density. malleability, ductility, etc. While some of the metals like gold are considered valuable because of their economical impact, others like iron are considered essential for human well-being. Let’s discuss a few metals and their role in our daily life.
1. Iron
Accounting for around 5% of the Earth’s crust and the 6th most common element in the universe, iron is a highly abundant and one of the most frequently used metals. In the modern periodical table of elements, iron is denoted by the symbol Fe and has an atomic number 26. It is primarily obtained from the minerals hematite and magnetite. Pure iron, typically about 99.8% pure, is of very little use on its own because it is very soft and brittle. The iron that we encounter in our daily life is usually an alloy made by melting and mixing one or more metals or non-metals with iron. For instance, the steel that we across every day is an alloy of iron with carbon, and stainless steel is an alloy of iron and chromium. Uses of iron in daily life include machinery, tools, vehicles, hulls of ships, structural elements for buildings, bridges, and aircraft. Iron is a non-toxic element and essential for almost all forms of life. The average human contains about 4 grams of iron in the blood as hemoglobin and carries oxygen from our lungs to the cells, where it is needed for tissue respiration. An average human being needs 10–18 milligrams of iron each day to avoid any potential cause of anemia.
2. Aluminum
Aluminum is a chemical element with the symbol Al and atomic number 13. It is the most abundant metallic element in the earth’s crust and also the most widely used nonferrous metal. Because of its chemical activity, aluminum never occurs in the metallic form in nature, but it is found in chemical compounds with other elements like bauxite. It is a very light metal with a density of 2.7 grams per cubic centimeters, about a third of that of steel. Together with lightweight, ductility, malleability, and corrosion resistance, aluminum is a particularly preferable material of choice for a variety of products including cans, foils, kitchen utensils, window frames, beer kegs, and airplane parts. Aluminum is an excellent heat and electricity conductor. This has made aluminum the first choice for major power transmission lines. It is also a superb heat sink for many applications that require heat to be drained away rapidly, such as in computer motherboards and LED lights.
3. Zinc
Zinc (Zn) is a blue-white metal of moderate strength, hardness, and ductility with atomic number 30. It is brittle and crystalline at ordinary temperatures, but it becomes ductile and malleable when heated between 110°C and 150°C. Like iron, zinc is also one of the essential metal nutrients for the well-being of the human body. The deficiency of zinc in the human body can cause a loss of appetite, decreased sense of taste and smell, slow wound healing, skin sores, and even cause birth defects. Although humans can tolerate relatively high zinc concentrations, too much zinc can cause serious health problems such as stomach cramps, skin irritations, vomiting, nausea, and anemia. High zinc levels can harm the pancreas, disrupt protein metabolism, and lead to arteriosclerosis. The majority of zinc is used to prevent corrosion in other metals. For instance, car body parts, traffic lamps, safety barriers, and suspension bridges are all made of steel galvanized with zinc. Another house of zinc includes being used as a pigment in plastics, cosmetics, wallpapers, printing inks, and other products. It also serves as a catalyst and heat disperser in rubber manufacturing.
4. Copper
Copper is considered the earliest metal discovered by prehistoric human beings. It is a reddish-brown colored metal with a face-centered cubic crystalline structure. In the modern periodic table, copper is denoted by the symbol Cu and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. Traditionally it has been one of the metals used to make coins, along with silver and gold; however, it is the most common of the three and therefore the least valued. Nowadays, most copper is used in electrical equipment such as wiring and motors. This is because it conducts both heat and electricity very well, and can be drawn into wires. It also has uses in construction (for example roofing and plumbing), and industrial machinery (such as heat exchangers). Copper is an easily molded base metal that is often added to precious metals to improve their elasticity, flexibility, hardness, color, and corrosion resistance. Copper alloys are also valued for their acoustic quality, especially brass, an alloy of copper and zinc. Because of its ability to absorb both magnetic and radio waves, it is the most reliable material for EM-safe utensils.
5. Gold
Gold, the shining yellow embodiment of wealth, is a metal denoted by the symbol Au and atomic number 79 in the modern periodic table. It is one of the least reactive chemical elements under standard temperature and pressure conditions. It is a soft metal and is usually alloyed to give it more strength. It is a good conductor of heat and electricity and is unaffected by air and most reagents. Almost 75% of the total mined gold is used for jewelry-making purposes. Gold is resistant to most acids, though it does dissolve in aqua regia (a mixture of nitric acid and hydrochloric acid), which forms a soluble tetrachloroaurate anion. Dentists sometimes use gold alloys in fillings, and a gold compound is used to treat some cases of arthritis. Gold nanoparticles are increasingly being used as industrial catalysts. Vinyl acetate, which is used to make PVA (for glue, paint, and resin), is made using a gold catalyst.
6. Silver
Silver (Ag), a white shiny metal renowned for its aesthetic beauty and electrical conductivity. In the modern periodic table of elements, Silver is denoted by the symbol Ag and atomic number 47. Because of its comparative scarcity, brilliant white color, malleability, ductility, and resistance to atmospheric oxidation, silver has long been used in the manufacture of coins, ornaments, and jewelry. Silver is an integral component in electrical switches that power your electronics and is widely used in high-end electronic devices, printed circuits, and audio/video components. It has also been used in photography for centuries, due to its light sensitivity. Traditional photography uses film covered in silver halide crystals which set when exposed to light creating a vivid picture
7. Mercury
Mercury, also known as quicksilver or hydrargyrum, is the only liquid metal at room temperature and has a shiny lustrous look. In the modern periodic table, mercury is denoted by the symbol Hg and atomic number 80. It occurs almost all around the world, in trace amounts, as a deposit called cinnabar (mercury sulfide). Although mercury is a toxic metal, there are several crucial applications associated with it. For instance, it is used to bind the alloy particles together into strong, durable, and solid dental amalgams. Another mercury compound, merbromin (Mercurochrome), is a topical antiseptic used for minor cuts and scrapes that is still in use in some countries. In its gaseous form, mercury is used to make mercury-vapor lamps and neon-advertising lights. It is also used in thermometers because it has a large thermal expansion that remains constant over a large temperature range, although it is being phased out in favor of safer liquids.
8. Lead
Lead is a metal commonly known for its extremely high density and radioactive shielding. In the modern periodic table, element lead is denoted by the symbol Pb and atomic number 82. Although it is one of the heaviest material known to mankind, it is soft, malleable, and have a low melting point in comparison to other materials. Naturally occurring lead is a mixture of four isotopes: _{ }^{208}{Pb}, _{ }^{207}{Pb}, _{ }^{206}{Pb}, and _{}^{204}{Pb}. Lead has been used by humans for centuries dating back to 7000 BC. Ancient Romans used lead to make paints and pipes corrosion-free. Nowadays, a major portion of the commercial production of lead contributes to the manufacturing of lead-acid batteries. In laboratories and industries, lead is used to line tanks that hold corrosive liquids, such as sulfuric acid. The toxic nature of lead has also made it employable in making bullets since the Middle Ages. Copper alloys with larger concentrations of lead are used in ball bearings.
9. Nickel
Nickel is a strong, shiny, silvery-white metal that is ubiquitously present in our daily lives. It appears in everything from the batteries that power our television remote controls to the stainless steel that makes up our kitchen sinks. In the modern periodic table, the element nickel is represented by the symbol Ni and the atomic number 28. Although nickel is the fifth most abundant element present on the earth, pure nickel is rare because it readily forms oxides by reacting with the oxygen present in the atmosphere. It is mostly found in iron ores as a stable iron-nickel alloy. Nickel is very strong, ductile, and resistant to corrosion, which makes it an excellent material for strengthening metal alloys that can further be shaped into wires, rods, tubes, and sheets. Nichrome, a nickel-chromium alloy with trace amounts of silicon, manganese, and iron, is a popular material for electric heater’s heating element. Another popular use of nickel is nickel-metal hydride batteries, which can easily be found in several electric appliances such as remotes, electric torches, etc. Several alloys of nickel are also used in boat propeller shafts and turbine blades.
10. Titanium
Titanium is a lustrous, silver-colored metal that is known to have particularly high strength and low density. Named after the Titans of the Greek Mythology, titanium is represented by the symbol Ti and the atomic number 22 in the modern periodic table. It occurs naturally within several mineral deposits widely distributed in the Earth’s crust and lithosphere, and it is also present in almost all living organisms, as well as in water bodies. Titanium is used in a wide number of industries ranging from aerospace to jewelry making. It is valued for being highly resistant to corrosion, particularly from chlorine and seawater, which makes it a material of choice in the manufacturing of condenser pipes for power plants. Titanium metal connects well with bone, so it also has surgical applications such as in joint replacements (especially hip joints) and tooth implants. Nanoparticles of titanium are also used in the manufacturing of sunscreens because it prevents the UV light from reaching the skin.
