Metals and Non-metals

Metals

• Metals are useful materials, fundamental to making objects
• Metals are strong, tough, and can withstand being dropped and heavy weights without breaking or cracking
• Metals can be bent and shaped, making them malleable and useful for hammering
• Metals can be drawn out into wires, a characteristic known as ductility
• Freshly cut or polished metals exhibit a shiny appearance
• Metals produce a ringing sound when struck, described as sonorous
• Most metals have high melting and boiling points
• Metals are good conductors of heat, feeling cold upon touch due to heat energy transfer
• Certain metals, including iron, steel, nickel, and cobalt, are magnetic
• Metals are good conductors of electricity, facilitating electric current flow

Non-metals

• Non-metals are useful due to their chemical reactions with other substances
• Non-metals appear dull, lacking the reflective properties of metals
• Solid non-metals are brittle and can shatter upon impact
• Most non-metals are poor conductors of heat, making them suitable for handles on cooking pans
• Most non-metals do not conduct electricity and are known as insulators
• Many non-metals exist as gases
• Non-metals that are not gases have low melting and boiling points

Comparing Metals and Non-metals

• Metals are mostly solid at room temperature, while many non-metals are gases
• Metals are shiny; non-metals are dull
• Metals typically do not shatter, whereas non-metals are brittle
• Metals are good conductors of heat and electricity
• Metals are malleable and ductile
• Metals are sonorous

Alloys

• Alloys are metal mixtures created by melting different metals together
• Atoms from different metals mix without bonding, resulting in properties distinct from their constituent metals
• Bronze is an alloy of copper and tin, known for being harder than either metal alone
• Steel, an alloy of iron and carbon, gains strength compared to pure iron
• Chromium and nickel are added to steel to prevent rust, making it suitable for cutlery
• Alloys have different properties compared to pure metals
• In pure metals, atoms are arranged in regular rows and can slide over one another
• Different-sized atoms disrupt the regular pattern, preventing sliding
• Alloys are coins are made from alloys rather than pure metals
• Pure metals are often too soft
• Silver-looking coins made from alloys of copper and nickel
• Copper-colored coins contain copper, zinc, and tin
• Coins are be hardwearing and malleable for stamping patterns
• Most gold jewellery is an alloy of gold and copper because pure gold is soft and wears away
• 24 carat gold is pure gold
• 18 carat gold is 18 parts gold and 6 parts other metals like copper, silver, or zinc
• Planes use aluminum alloys, as pure aluminum is not strong enough
• Duralumin, an alloy of aluminum with magnesium and copper, is five times stronger than pure aluminum
• Artificial joints are made of plastic and alloys, often alloys of titanium
• Modern alloys, such as Nitinol (nickel and titanium), have shape memory characteristics, returning to their original form when heated
• Brass is an alloy of copper and zinc, with different types containing varying amounts of these metals, and sometimes lead, aluminum, manganese, or silicon

Brass, Copper and Steel Properties

Common Alloys