Opener: Describe the earliest cell phone you remember. How have cell phones changed since then? Why is it important for cell phone developers to know.

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  • Opener:

    Describe the earliest cell phone you remember.

    How have cell phones changed since then?

    Why is it important for cell phone developers to know what the older versions were like?


  • Democritus400 B.C.

    Proposed that matter is made of about 100 basic kinds of tiny particles he called atomos that cant be divided into smaller particles.

    Nobody believed him.

  • His experiments with gasessuggested that matter wascomposed of tiny particles.He renewed interest in the idea of atoms.

  • Antoine Lavosier1780Known as the Father of Modern Chemistry Developed the theory of Conservation of MatterAntoineModern chemistry

  • John Dalton1803Atoms are all solid with uniform density (like a gum ball)Atoms are the smallest particles of nature.All atoms of the same element are identical.All atoms are indivisibleAtoms of different sizes can combine to make compounds.An atom, according to Dalton.

  • Marie Curie1898Credited with the discovery of the first radioactive elements.

    Theorizes that theses elements emit invisible rays called radiation

    First person to win Nobel Prizes in TWO different sciences (chemistry and physics).

    Discredits part of Daltons theory (indivisible atoms)Atoms must have smaller components

  • Credited for the discovery of the electron, because he realized the beam of light in a Crookes tube was really made of negative particles.

    Realized that electrons were smaller than atoms.

    This information discredited part of Daltons atomic theory

    Developed the Plum Pudding model of the atom

  • Experimented with magnets-

  • Experiment #2+

  • Conclusions?The stream of particles was NegativeOverall, atoms are...NeutralTherefore, atoms must also contain charges that are...Positive

  • Plum (electrons)Pudding(positivestuff)Today, it would probably be called the Chocolate Chip Cookie Model

  • Max Planck 1900Developed Quantum Theory.He discovers that energy is not given off in continuous amounts. Instead, energy is released in small packets that he calls quanta. This idea contradicts our common-sense ideas about energy and matter but it turns out to be correct!Energy acts like a particle!

  • Ernest Rutherford1910Performed Gold Foil Experiment.

    Discovered that atoms had a nucleus!

    Disproved Plum Pudding model.

    Won Nobel Prize for Chemistry.

  • The Gold Foil ExperimentBombard thin piece of gold foil with alpha particlesResult: some are deflected while others are unaffectedWhat does it all mean?

  • Dense, positively charged nucleus.Electrons surround the nucleus like bees around a hive.Atoms are mostly empty space.Problem: Why didnt electrons get pulled into the nucleus?

  • Neils Bohr1913Extended Quantum Theory to electrons in atoms!Electrons are in certain orbits at a specific distance from the nucleus.Only certain orbits were allowed.If an electron stayed in its orbit, it didnt lose any energy and would not fall into the nucleus.

  • Atomic Line SpectraHydrogen GasPrism or diffraction gratingExpected to see a nice progression of color just like normal BUT..

  • Atomic Line SpectraGas such as Neon or HydrogenPrism or diffraction gratingInstead he got just a few discrete lines of color!

  • Niels BohrPlanetary ModelCompares electrons orbiting the nucleus of an atom to planets orbiting around the sun.Electrons occupy distinct orbitals.Orbitals have certain energies and distances from the nucleus.Bohrs theory explains how light is given off a huge success!

  • For ElectronsNucleus3 22 13 1

  • Heisenberg/SchrodingerQuantum Mechanical Model/Electron Cloud Model Regions where electrons are most likely found are called electron clouds.

    Different types of orbitals have different shapes and different levels of energy.

  • James Chadwick1932Established the existence of the neutron.


  • 1980s The first atoms are seen with scanning tunneling microscopes



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