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Elements & Compounds

Elements & Compounds. Elements. An element is a substance made of only one atom and cannot be broken down into simpler substances in a chemical reaction. Compounds.

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Elements & Compounds

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  1. Elements & Compounds

  2. Elements • An element is a substance made of only one atom and cannot be broken down into simpler substances in a chemical reaction.

  3. Compounds • Compounds are groups of two or more elements that are bonded together and can be separated in to smaller substances in a chemical reaction.

  4. Periodic Table

  5. Aluminium (Al) • Atomic Number: 13 • Symbol: Al • Atomic Weight: 26.981539 • Discovery: Hans Christian Oersted (1825, Denmark), Wohler (1827) Word • Origin: Latin alumen: alum, an astringent and dyeing mordant • Aluminium has a melting point of 660.37°C, boiling point of 2467°C, specific gravity of 2.6989 (20°C), and valence of 3. Pure aluminium is a silvery-white metal. It is soft and light, a good conductor of heat and electricity. It can be easily formed, machined, or cast. It is also non-magnetic and non-sparking.  • It is used in kitchen utensils and exterior decorations. It is also used in electrical cables as it is light. It is used in drink cans as well and alloys of aluminium are used in making rockets and aircrafts.

  6. Copper (Cu) • Atomic Number: 29 • Symbol: Cu • Atomic Weight: 63.546 • Discovery: Copper has been known since prehistoric time. It has been mined for more than 5000 years. • Word Origin: Latin cuprum: from the isle of Cyprus, which is famed for its copper mines • Copper has a melting point of 1083.4 +/- 0.2°C, boiling point of 2567°C, specific gravity of 8.96 (20°C), with a valence of 1 or 2. Copper is reddish colored and takes a bright metallic luster. It is malleable, ductile, and a good conductor of electricity and heat.  • Copper is used in water pipes and cookware. Bronze and brass are alloys of copper. Brpnze and brass are used to make statues and medals and musical instruments respectively.

  7. Calcium (Ca) • Atomic Number: 20 • Symbol: Ca • Atomic Weight: 40.078 • Calcium Discovery: Sir Humphrey Davy Davy 1808 (England) • Word Origin:Latin calx, calcis: lime • The melting point of calcium is 839 +/- 2°C, boiling point is 1484°C, specific gravity is 1.55 (20°C), with a valence of 2. Calcium is a silvery white, soft alkaline earth metal.  • Calcium is essential for human nutrition. Calcium is also necessary for plant growth. Calcium compounds are used in making lime, bricks, cement, glass, paint, paper, sugar, glazes, as well as for many other uses.

  8. Mercury (Hg) • Atomic Number: 80 • Symbol: Hg • Atomic Weight: 200.59 • Discovery: Known to the ancient Hindus and Chinese. Mercury has been found in Egyptian tombs dating to 1500 B.C. • Word Origin: from the Planet Mercury; Hg is the symbol for Hydrargyrum, which means liquid silver • Mercury has a melting point of -38.842°C, boiling point of 356.58°C, specific gravity of 13.546 (20°C), and a valence of 1 or 2. Mercury is a heavy, silvery-white metal. It is a relatively poor conductor of heat, but a fair conductor of electricity. It is also poisonous. • Mercury is amalgamated with gold to facilitate the recovery of gold from its ores. Mercury is used to make thermometers, diffusion pumps, barometers, mercury vapor lamps, mercury switches, pesticides, batteries, dental preparations, antifouling paints, pigments, and catalysts. 

  9. Iron (Fe) • Atomic Number: 26 • Symbol: Fe • Atomic Weight: 55.847 • Discovery: Known since prehistoric time • Word Origin: Latin ferrum; Anglo-Saxon iron • The melting point of iron is 1535°C, boiling point is 2750°C, specific gravity is 7.874 (20°C), with a valence of 2, 3, 4, or 6. Pure iron is chemically reactive and corrodes rapidly, especially in moist air or at elevated temperatures.  • Iron is used in the manufacturing of steel, railings, grills and cooking uitensils.

  10. Magnesium (Mg) • Atomic Number: 12 • Symbol: Mg • Atomic Weight: 24.305 • Discovery: Recognized as an element by Black 1775; Isolated by Sir Humphrey Davy 1808 (England) • Word Origin:Magnesia, a district in Thessaly, Greece • Magnesium has a melting point of 648.8°C, boiling point of 1090°C, specific gravity of 1.738 (20°C), and valence of 2. Magnesium metal is light (one-third lighter than aluminum), silvery-white, and relatively tough. The metal tarnishes slightly in air.  • Magnesium is used in making fireworks and distress flare. It is also used in milk.

  11. Gold (Au) • Atomic Number: 79 • Symbol: Au • Atomic Weight: 196.9665 • Discovery: known since prehistoric time • Word Origin: Sanskrit Jval; Anglo-Saxon gold; meaning gold - also Latin aurum, shining dawn • The melting point of gold is 1337.58°C, boiling point is 3080°C, specific gravity is 18.88 (20°C), with a valence of 1 or 3. Gold is a soft, malleable, yellow metal. Gold is also a good conductor of heat and electricity. • Gold is used in coinage and dental work, plating, jewellery and reflectors.

  12. Silver (Ag) • Atomic Number: 47 • Symbol: Ag • Atomic Weight: 107.8682 • Discovery: Known since prehistoric time. Man learned to separate silver from lead as early as 3000 B.C. • Word Origin: Anglo-Saxon Seolfor or siolfur; meaning 'silver', and Latin argentum meaning 'silver‘ • The melting point of silver is 961.93°C, boiling point is 2212°C, specific gravity is 10.50 (20°C), with a valence of 1 or 2. Pure silver has a brilliant white metallic luster. It is slightly harder than gold and it has the highest electrical and thermal conductivity of all metals. • Silver is used in photography, dental compounds, solder, brazing, electrical contacts, batteries, mirrors, and printed circuits. Sterling silver (92.5% silver, with copper or other metals) is used for silverware and jewelry. Silver fulminate (Ag2C2N2O2) is a powerful explosive. Silver iodide is used in cloud seeding to produce rain. Silver chloride can be made transparent and is also used as a cement for glass. Silver nitrate, or lunar caustic, is used extensively in photography. 

  13. Oxygen gas (O) • Atomic Number: 8 • Symbol: O • Atomic Weight: 15.9994 • Discovery: Joseph Priestly, Carl Wilhelm Scheele, 1774 9 (Sweden/England) • Word Origin: Greek: oxys: sharp or acid and Greek: genes: born, former... 'acid former‘ • Melting Point (°K): 54.8 • Boiling Point (°K): 90.19 • Oxygen gas is colorless, odorless, and tasteless.  • Oxygen helps people to breathe and remove impurities when making steel. It also supports respiration and combustion.

  14. Hydrogen gas (H) • Atomic Number: 1 • Symbol: H • Atomic Weight: 1.0079 • Discovery: Cavendish, 1766. Hydrogen was prepared for many years before it was recognized as a distinct element. • Word Origin: Greek: hydro, water; genes, forming Named by Lavoisie • Melting point: -259.2°C • Boiling point: -252.762°C • Valence: 1 • Hydrogen gas is used in making margarine and rocket fuel.

  15. Nitrogen gas (N) • Atomic Number: 7 • Symbol: N (Az, French) • Atomic Weight: 14.00674 • Discovery: Daniel Rutherford 1772 (Scotland): Rutherford removed oxygen and carbon dioxide from air and showed that the residual gas would not support combustion or living organisms. • Word Origin: Latin: nitrum, Greek: nitron andgenes; native soda, forming. Nitrogen was sometimes referred to as 'burnt' or 'dephlogisticated' air. The French chemist Antoine Laurent Lavoisier named nitrogen azote, meaning without life. • Melting point: -209.86° C • Boiling point: 195.8° C • Valence: 3, 5 • Nitrogen gas Is used in plant fertilisers and they help in the food industry in packing for food as they are freezing agents for food.

  16. Carbon (solid) (C) • Atomic Number: 6 • Symbol: C • Atomic Weight: 12.011 • Discovery: Carbon exists free in nature and has been known since prehistoric time. • Word Origin: Latin carbo, German Kohlenstoff, French carbone: coal or charcoal • Melting Point (K): 3820 • Boiling Point (K): 5100 • Graphite: used in pencil lead • Diamond: used in jewellery and cutting tools • Charcoal: used in the calligraphy ink and printer ink

  17. Helium (He) • Atomic Number: 2 • Symbol: He • Atomic Weight: 4.00260 • Discovery: Janssen, 1868, some sources say Sir William Ramsey, Nils Langet, P.T. Cleve 1895 • Word Origin: Greek: helios, sun. Helium was first detected as a new spectral line during a solar eclipse. • Melting Point (°K): 0.95 • Boiling Point (°K): 4.216 • Helium is a very light, inert, colorless gas.  • Helium is used in the study of superconductivity, as an inert gas shield for arc welding, as a protective gas in growing silicon and germanium crystals and producing titanium and zirconium, for pressuring liquid fuel rockets, for use in magnetic resonance imaging (MRI), as a cooling medium for nuclear reactors, and as a gas for supersonic wind tunnels. Helium is used for filling balloons and blimps.

  18. Chlorine gas (Cl) • Atomic Number: 17 • Symbol: Cl • Atomic Weight: 35.4527 • Discovery: Carl Wilhelm Scheele 1774 (Sweden) • Word Origin: Greek: chloros: greenish-yellow • Melting Point (K): 172.2 • Boiling Point (K): 238.6 • Valence: 1, 3, 5, 7 • Chlorine is yellowish-green. • Chlorine gas is used in bleaching bacteria and kills bacteria. It is also used in making plastic (PVC).

  19. Sodium (Na) • Atomic Number: 11 • Symbol:Na • Atomic Weight: 22.989768 • Word Origin:English soda and Medieval Latin sodanum: headache remedy; Latinnatrium: sodium carbonate • Melting point: 97.81 • Boiling point: 882.9 • Valence: 1 • Sodium is a bright silvery metal. • Sodium chloride is important for animal nutrition. Sodium compounds are used in the glass, soap, paper, textile, chemical, petroleum, and metal industries. Sodium is used in preparing tetraethyl lead. It is used in the reduction of organic esters and preparation of organic compounds.

  20. Sulfur (S) • Atomic Number: 16 • Symbol: S • Atomic Weight: 32.066 • Discovery: Known since prehistoric time. • Word Origin: Sanskrit: sulvere, Latin: sulpur, sulphurium: words for sulfur or brimstone • Melting point: 112.8°C (rhombic) or 119.0°C (monoclinic) • Boiling point: 444.674°C • Valence: 2, 4, 6 • Sulfur is a yellow, brittle, odourless solid. • Sulfur is used to make rubber tougher and stronger. It is also used to make pesticides as it kills germs and harmful bacteria. It is also used in medicinal drugs.

  21. Neon (Ne) • Atomic Number: 10 • Symbol: Ne • Atomic Weight: 20.1797 • Discovery: Sir William Ramsey, M.W. Travers 1898 (England) • Word Origin: Greek neos: new • Melting point: -248.67°C • Boiling point: -246.048°C • Valence: 0 • Neon is used to make neon signs. Neon and helium are used to make gas lasers. Neon is used in lightning arrestors, television tubes, high-voltage indicators, and wave meter tubes. 

  22. These are only some of the common elements. Hope you enjoyed it!!!

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