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Scanning Tunneling Microscope

Scanning Tunneling Microscope. later scientists found that not only can you see the atoms on the surface, but the instrument allows you to move individual atoms across the surface. AINEEN HÄVIÄMÄTTÖMYYDEN LAKI:

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Scanning Tunneling Microscope

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  1. Scanning Tunneling Microscope • later scientists found that not only can you see the atoms on the surface, but the instrument allows you to move individual atoms across the surface

  2. AINEEN HÄVIÄMÄTTÖMYYDEN LAKI: • Kemiallisessa reaktiossa ei aineen kokonaismassassa tapahdu muutosta. (Lavoisier 1785) • VAKIOISTEN PAINOSUHTEIDEN LAKI: • Sama kemiallinen yhdiste sisältää aina samoja alkuaineita samoissa massasuhteissa (Proust 1799)

  3. Kerrannaisten painosuhteiden laki: • Jos kaksi alkuainetta A ja B muodostavat keskenään useamman kuin yhden yhdisteen, ovat ne massat A:ta, jotka yhtyvät samaan massaan B:tä, yksinkertaisessa kokonaislukusuhteessa toisiinsa. (Dalton 1804)

  4. TILAVUUSSUHTEIDEN LAKI: • Kaasujen reagoidessa keskenään kuluneet kaasutilavuudet ovat yksinkertaisessa kokonaislukusuhteessa toisiinsa sekä myös syntyvien aineiden tilavuuksiin, jos nämä ovat kaasuja. (Gay-Lussac 1808)

  5. AVOGADRON LAKI: • Samassa lämpötilassa ja paineessa yhtä suuret tilavuudet eri kaasuja sisältävät yhtä monta kaasuhiukkasta. (Avogadro 1811)

  6. Dalton proposed a theory of matter based on it having ultimate, indivisible particles to explain these laws • Each element is composed of tiny, indestructible particles called atoms • All atoms of a given element has the same mass and other properties that distinguish them from atoms of other elements • Atoms combine in simple, whole-number ratios to form molecules of compounds • In a chemical reaction, atoms of one element cannot change into atoms of another element • they simply rearrange the way they are attached

  7. Thomson’s Plum Pudding Atom • the structure of the atom contains many negatively charged electrons • these electrons are held in the atom by their attraction for a positively charged electric field within the atom • there had to be a source of positive charge because the atom is neutral • Thomson assumed there were no positively charged pieces because none showed up in the cathode ray experiment

  8. Alpha Particles Striking Screen Rutherford’s Experiment Radioactive Sample Lead Box Fluorescent Screen Gold Foil

  9. Over 98% of the a particles went straight through • About 2% of the a particles went through but were deflected by large angles • About 0.01% of the a particles bounced off the gold foil • “...as if you fired a 15” cannon shell at a piece of tissue paper and it came back and hit you.”

  10. Plum Pudding Atom • • • • if atom was like a plum pudding, all the a particles should go straight through • • • • • • • • • • • • • • • • • • a few of the a particles do not go through Nuclear Atom . most a particles go straight through . . some a particles go through, but are deflected

  11. Alkuaineatomin järjestysluku (Z ) = protonien lukumäärä atomiytimessä • Alkuaine on aine, jonka kaikilla atomeilla on sama järjestysluku (Z)

  12. Symbol Number of Protons Number of Neutrons A, Mass Number Percent Natural Abundance Ne-20 or 10 10 20 90.48% Ne-21 or 10 11 21 0.27% Ne-22 or 10 12 22 9.25%

  13. lithium sodium potassium rubidium cesium

  14. beryllium magnesium calcium strontium barium

  15. fluorine chlorine bromine iodine astatine

  16. helium neon argon krypton xenon

  17. = Alkali Metals = Alkali Earth Metals = Noble Gases = Transition Metals = Halogens = Lanthanides = Actinides

  18. AINEMÄÄRÄ (n), YKSIKKÖ = MOOLI (mol) • MÄÄRITELMÄ: • Mooli on ainemäärä sellaisessa systeemissä, joka sisältää yhtä monta alkeisyksikköä (eng. elementary unit) kuin 0,012 kg:ssa hiili-12 (12C) on hiiliatomeja. (Alkeisyksikkö on mainittava, ja se voi olla atomi, molekyyli, ioni, radikaali, elektroni tms.)

  19. AVOGADRON VAKIO NAILMOITTAA KY-SEISEN LUKUMÄÄRÄN = 6,022 x 1023 1/mol • MOOLIMASSA (M) = YHDEN MOOLIN MASSA • M(12C) = 12 g/mol • AINEMÄÄRÄ n = m/M

  20. mole = number of particles equal to the number of atoms in 12 g of C-12 • 1 atom of C-12 weighs exactly 12 amu • 1 mole of C-12 weighs exactly 12 g • The number of particles in 1 mole is called Avogadro’s Number =6.0221421 x 1023 • 1 mole of C atoms weighs 12.01 g and has 6.022 x 1023 atoms • the average mass of a C atom is 12.01 amu

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