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SNC 1D1 – Properties of Non-Metals and Metalloids Non-metals usually have the following properties: Most are gases at room temperature. Solid non-metals have no metallic lustre. Some such as sulphur are brightly coloured. Solid non-metals are brittle.
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SNC 1D1 – Properties of Non-Metals and Metalloids Non-metals usually have the following properties: Most are gases at room temperature. Solid non-metals have no metallic lustre. Some such as sulphur are brightly coloured. Solid non-metals are brittle. Usually poor conductors of electricity and thermal energy. Example: Carbon (C), sulfur (S), oxygen (O)
Sulphur(A Solid Non- Metal) • a brittle, bright yellow solid. • sulphur burns with a blue flame. • sulphur is found near volcanoes and hot springs. • links between sulphur atoms in proteins make hair curly. • sulphur is also used to make chemicals like sulphuric acid
Mining Sulphur Near an Active Volcano Crystallized sulphur
Non-Metals in the Air • Most gases in the air are non-metals. 78 % nitrogen 21% oxygen 0.9% argon 0.1% neon, helium, krypton, and compounds like carbon dioxide. • Oxygen is required for all animals to breathe. Plants make oxygen in photosynthesis • Nitrogen makes up 78 % of the atmosphere. Nitrogen in SCUBA tanks can cause “the bends” if divers rise to the surface too quickly.
Halogens • Group 17 elements such as fluorine, chlorine and bromine are highly reactive. • Most halogens are toxic. • Chlorine and bromine can be used to disinfect water for drinking or swimming. • Iodine combined with alcohol is commonly used as a disinfectant to clean wounds. • Iodine tablets can be used to clean water when camping.
Chlorine, bromine, and iodine Tincture of iodine Used in disinfecting.
Noble Gases: • Noble gases in group 18 rarely react. • Helium (He) filled balloons rise in the air because they are lighter than air. • Xenon (Xe) is used in the bluish high-intensity headlights of vehicles. • Neon (Ne) and argon (Ar) give off brightly coloured light when electricity passes through them.
Xenon Headlamps Helium Balloons vs Hot air balloons
Properties of Metalloids: • Metalloids have propertiesin between those of metals and non-metals. • All metalloids are solids at room temperature. • Some metalloids are weak conductors of electricity and thermal energy.
Semiconductors • Some metalloids conductelectricity to some degree • Silicon (Si) and Germanium (Ge) are useful in making semiconductors. • Semiconductors are used to make parts of electric circuits. • The flow of electricity in a semiconductor can be more easily controlled than in materials such as copper. • This allows computer chips to do complex tasks. • Another metalloid arsenic has been used as a wood preservative and was used as an insecticide for fruit trees. • It can escape into the environment and contaminate soil, water, air and food.
Semiconductor wafer
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