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Flashcards in atomic physics Deck (20):

Geiger-Marsden experiment

most of the charged particles passed through gold foil, minor scatterings


Rutherford's conclusions from gold foil experiment

positive charge concentrated in nucleus, and most of the mass located there. atoms are almost all empty space


radii of nuclei from charged particle scattering

loss of kinetic energy=gain of electrostatic potential energy


nuclear planetary model

Rutherford from gold-foil experiment
electrons orbit nucleus with electrostatic attraction providing needed centripetal force


limitations of nuclear model

electrons should be accelerating, radiating electromagnetic radiation and gradually losing energy, but this does not happen


atomic spectra

all objects emit electromagnetic waves, but at different wavelengths (solids mostly continuous, individual atoms don't and are characteristic of the atom)
absorption by gas at same frequencies it would emit (example of resonance)


experiment to find atomic emission spectra

high voltage through two electrodes at ends of sealed glass at low pressure (electrons are emitted by cathode towards anode by electric field)
diffraction grating used to disperse light into spectra


production of absorption spectra

a white light sent through a glass container with a low pressure gas, is then dispersed with a grating


fraunhofer lines

dark lines showing the elements in an atmosphere due to absorption


evidence for atomic energy levels

emission and absorption spectra of gases at low-pressure consist of discrete lines


evidence for quantization of energy in atoms

atomic spectra, when a photon is emitted, then its energy must be equal to the difference of the energy between the different electron energy states in between emissions. therefore can only take certain energy levels


when is a photon emitted or absorbed

emission when electrons lower energy level, or absorb when increase


conversion of electron volts to J

eV=1.60217657 × 10-19 joules


de Broglie hypothesis

since photons have momentum p=h/wavelength, he suggests all particles have wave-like properties and wavelength (wavelength=h/p=h/mv)


wave-particle duality

all matter and energy exhibits wave-like and particle-like properties


experiment verifying de Broglie's

Electron diffraction, where a maximum of electrons seen at 50 degrees suggesting constructive interference


kinetic energies of the atomic energy states



electron in a box model in origins of energy levels

the electron's probability wave has to fit boundary conditions, which leads to discrete energy levels (quantization)


Schrödinger's model of hydrogen atom

the electrons are given wave functions, but it has no defined position. The square of the wave-function at a point gives the probability of its location


Artificial transmutation

Nucleus artificially made from another