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Chapter 6-7

Chapter 6-7. The Periodic Table, Periodic Law, and The Elements. Periodic Table and Periodic Law. Periodic Table. Elements are arranged in increasing atomic number according to similar properties in columns or groups It was developed over decades

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Chapter 6-7

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  1. Chapter 6-7 The Periodic Table, Periodic Law, and The Elements

  2. Periodic Table and Periodic Law

  3. Periodic Table • Elements are arranged in increasing atomic number according to similar properties in columns or groups • It was developed over decades • 1790’s- Lavoisier compiled a list with 23 elements

  4. John Newland • 1864- arranged elements by the “law of octaves” • (1st arranged) – right idea but not exactly right after the first 14 or so.

  5. Demitri Mendeleev (1834-1907) • Russian • 1869- designed the “modern table” Moseley slightly rearranged based on atomic number and created our basic modern table

  6. Periodic Law • There is a periodic repetition of properties when arranged by atomic number

  7. Groups • Also called families (vertical columns) • Share similar properties • End in same e- configuration • Same valence e- • Same reactivity

  8. Period • Horizontal rows • Share same highest energy level

  9. Periodic trends • Atomic radius- half the distance between the nuclei of identical atoms that are bound together • Group trend: increase down Atomic radius increases down because as you go down there are more electrons and more energy levels and with each energy level you get further from the nucleus. • Periodic trend: decrease left to right Atomic radius decreases from left to right because when you go across a period electrons are being added to the same energy level, which makes a stronger attraction and pulls electrons closer to the nucleus resulting in a smaller atom.

  10. Ionic radius • Ion- has a charge (+ or -) – when an atom gains or loses an e- • Cation- positive ion- lost e- - smaller than neutral • Anion- negative ion- gained e- - larger than neutral *** same trend as atomic radius

  11. Ionization energy • Energy required to remove an e- • Each e- has its own energy • 1st IE<2nd<3rd • Group trend: decreases down • Period trend: increases across • These trends are both due to the fact that electrons are more difficult to remove from stable elements

  12. Electron affinity • Energy change that occurs when an e- is acquired by a neutral atom • Fe + e- Fe-

  13. Electronegativity • Relative ability of an atom to attract electrons to itself in a bond • Pauling electronegativity scale • Period: increase left to right • Group: decreases down • General trend: increase up and right F=most electronegative O=second most Fr=least

  14. The Elements

  15. Hydrogen and helium • Unique- can both occupy 2 groups • H= 1A & 7A • He= 2A & 8A • 99% of Universe • 76% = H • 23% = He

  16. Alkali Metals: groups 1 or 1A • Alkali comes from Arabic- “ashes” • All are very reactive, react violently with H2O, soft, low density, low melting pts. • Li- batteries, dehumidifiers, bipolar disorder medication • Li2CO3 -in glass, airplane parts • Na- salt, vapor lamps, heat exchanger in nuclear reactors, electrolyte • K- electrolyte for muscles, one of 3 main ingredients in fertilizer • KNO3 in large scale fireworks and gun powder

  17. Alkaline Earth metals: group 2 or 2A • All but Be form oxides that will not melt and form basic solutions • Less reactive than 1A • More dense, higher melting points • Be- with Al, Si, and O makes beryl (emerald/ aquamarine), moderates neutrons in reactors, Be/Cu alloys are used for tools where no sparks can be formed like refineries • Mg- backpack frames, bicycle wheels, “mag” wheels, oxide used to line furnaces, every chlorophyll has 1 Mg+2, muscle function and metabolism- found in “hard” H20 with Ca +2

  18. Alkaline earth metals continued… • Sr- crimson fireworks • Ba- paints, additive in glass, diagnostic tool in medicine • Ra- highly radioactive, once used in glow in the dark paint for watches

  19. Aluminum Group: group 13 or IIIA • B- metalloid, Borax is the name of the mined compound • B/Si/O=borosilicate=pyrex • Mined in the Mojave Desert Boric acid: disinfectant, ant repellant Boron nitride: second hardest substance

  20. Aluminum group continued…. • Al- cans, foil • most abundant metal on earth • 3rd most abundant element on earth • Mined from bauxite • Strengthens ceramics, heat- resistant fabric, ruby and sapphires are mainly Al2O3 • Al2(SO4)3- alum- antiperspirant and water purification

  21. Al group Continued….. • Ga- used in some thermometers from 30o to 2400oC • Gallium arsenide produce photoelectric cells • Solar power=calculators • 10x more efficient than Si chips • Gallium nitride- used for blue lasers (can triple storage)

  22. Carbon group: group 14 or IVA • C- has its own study- organics • Exist in at least 4 natural forms – diamond, graphite, coal (soot), Buckminster fullerene

  23. Carbon group Continued….. • Si- computer chips, solar cells, 2nd most abundant element in the crust, most common form is silica, (Si02) A.K.A sand, glass, quartz • Silicon carbide- industrial abrasive (carborundum)

  24. Carbon group Continued…. • Ge- metalloid- solid state electronics • Pb- toxic, was in paint, may have been 1st pure metal, additive in glass, causes brain damage • Sn- coating for cans, Bronze, construction materials, foil

  25. Nitrogen Group: Group 15 or VA • N- colorless, odorless, unreactive-= 80% of air; compounds- fertilizer, explosives (TNT), DNA, Ammonia (cleaning), dyes, nitroglycerin • HNO3- used to etch metal plates and other industrial uses

  26. Nitrogen group continued.. • P- has 3 allotropes (white, red, black), phosphoric acid, processed cheese, laxatives, matchbox, baking powder, fertilizer, ATP, DNA, detergents

  27. Nitrogen continued… • As- toxic, Arsenic sulfide was used as medicine, metalloid • Sb- antimony sulfide was used as a cosmetic to darken eyebrows and make eyes appear larger, 5% of modern Pb storage batteries, Sn/Sb alloy can be molded (tableware)- metalloid

  28. Nitrogen Continued…. • Bi- Pepto Bismol, Bi/Pb/Sn/Cd alloy called woods metal used as a plug in sprinkler system

  29. Oxygen Group: group 16 or IVA • O- 2 allotropes 02/03---most abundant element on earth -bleaching agent 50% of earth crust= 20% of air

  30. Oxygen Continued… • S- 10 allotropes -Cinnabar, galena -can be found in nature in pure form (yellow) H2S04= fertilizer production, steel, paper, paint silver tarnish is H2S + AgAg2S

  31. Oxygen continued… • Se- works with Vitamin E to prevent cell damage, can be toxic= RDA= 10 mg, toxic L050= 200 m/m3, can convert light to electricity- used in solar panels, photographer meters, photocopiers, semiconductors • Te- metalloid- semiconductors- rare • Po- named for Poland- rare, radioactive, toxic

  32. Halogens: Group 17 or VIIA • Most reactive nonmetals- “halo”- salt “genero”- form= salt formers • State of matter at room temp. • F, Cl= gas • Br= liquid • I, (At)= solid

  33. Halogens continued…. • F- most electronegative element- most active element • “fluere”- latin, “to flow”- added to H20 and toothpaste to prevent decay, teflon= F/C compound reacts with U to form gases (U enrichment) U-235

  34. Halogens Continued… • Cl- deadly gas in its pure form -can be a disinfectant -NaCl=bleach -nerve blocker in medicine HCl- removes rust or algae, etc. (muriatic) -mixed with oil=PVC (Poly Vinyl Chloride)

  35. Halogens Continued… • Br- photographic film • I- photographic film, needed to maintain a healthy thyroid (controls growth and metabolic rate), disinfectant, iodized salt • At- radioactive, man-made

  36. Nobel Gases: group 18 or VIIIA • All were considered inert (nonreactive) until the 1960’s • He, Ne, Rn- still no compounds

  37. Noble gases continued… • He- used in balloons, blimps, and dive tanks -liquid form=coolant -superconducting magnets -pale yellow “neon” lights • Ne- first “neon” light -bright orange

  38. Noble gases continued… • Ar- insulation in windows, 1% of air, blue “neon” light, atmosphere of incandescent lights, high temp. welding • Kr- used as insulation in windows • Xe- 1st to form a compound • Rn- deadly radioactive gas from U decay, found under homes

  39. Transition metals • D-block- groups 3-12 – B elements • Various uses and forms -Cobalt 60=chemotherapy -Fe= construction -Fe, Co, Ni= magnets -Ag, Au, Pt= “precious” metals -Cu= wire -Co= red blood cells -Mn= cell respiration

  40. Inner transition metals • The “f” block • Lanthanide and actinide series • Ce= used to remove C from steel, movie projectors, search lights • Pu= 239 reactor fuel • Am= smoke detectors • Nb, Pr= welding goggles • Yb, Eu= TV screens, computer monitors

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