Quantum Mechanics Already Graded A+
Max Planck : German physicist who solved the problem of why different wave lengths are
emitted at different temperatures- proposed that the energy absorbed or emitted by an object could
only occur in "pieces"- which he called quantum
Wener Heisenberg : Ge...
Max Planck ✅1858-1947: German physicist who solved the problem of why different wave lengths are
emitted at different temperatures- proposed that the energy absorbed or emitted by an object could
only occur in "pieces"- which he called quantum
Wener Heisenberg ✅1901-1976: German theoretical physicist- published his theory on quantum
mechanics when he was 23- concluded that it is impossible to make a measurement on an object
without disturbing the object
Albert Einstein ✅1879-1955: German theoretical physicist used Planck's quantum theory to explain the
photoelectric effect-- proposed that the light itself consisted of small particles of energy called photons
(quanta of energy) *he believed light behaves like a particle, not a wave
Neils Bohr ✅1885-1962: Danish theoretical physicist- Bohr's Atomic Model (started with the hydrogen
atom)
he proposed that only certain colors of light were produced because the energy of an electron was
quantized (discontinuous)
Wolfgang Pauli ✅1900-1958: Austrian theoretical physicist- worked with Bohr and determined the
Exclusion Principle
Louis de Broglie ✅1892-1987: French theoretical physicist- proposed the idea of "matter waves"-
electrons also have wave properties but they are too small to see-- wavelength = h/(mass)(frequency)
Hund ✅1896-1997: Germany theoretical physicist studied orbitals in atoms and molecules
Bohr's Atomic Model ✅electrons were only allowed to move around the nucleus in certain orbits that
corresponded to diff amounts of energy- the small the electron's energy (or energy level)
*the difference in energy between the energy levels corresponds to the energy/color of the observed
light.
, Bohr's Atomic Model failure ✅though it works for hydrogen, it failed to predict spectra correctly for
other elements. Also, later experiments have shown that the idea of electrons "orbiting" the nucleus
was not correct.
quantum ✅a piece of energy
Planck's equation ✅E=hv
E: energy, which measured in Joules
h: planck's constant- 6.6262 X 10-34 Js
v: frequency, which is measured in Hz
*gives the relationship between the frequency and the energy of radiation- because that energy is
quantized, it is restricted to certain quantities
photons ✅packets of radiation (that light itself consisted of these things)
How did Einstein's theory explain the photoelectric effect? ✅1. energy absorption is an all or nothing
process- an electron either absorbs all of the photon's energy or none of the photon's energy
2. the frequency (or energy) of the photon (and not the intensity/number) is what determines whether
or not the photon is absorbed.
Heisenberg's Uncertainty Principle ✅It's impossible to know precisely both the velocity and the position
of a particle at the same time
Erwin Schrodinger ✅1887- 1961: Austrian theoretical physicist- took over Planck's position after he
retired - his wave equation is the basis for the quantum mechanical model of the atom
Schrodinger's Wave Equation ✅The solutions to Schrodinger's wave equation determine the probability
for finding an electron in a particular volume around the nucleus
Quantum Mechanical Model of an Atom ✅1. the energy of electrons is quantized
2. Electrons behave like waves
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