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Chapter 23: Atomic Physics :checkered_flag: (Early model of the Atom…
Chapter 23: Atomic Physics :checkered_flag:
Early model of the Atom
Rutherford
Positive charge is concentrated in the center of the atom, nucleus
Atoms emit cetain discrete characteristics frequencies of electromagnetic radiation
Rutherford model is unable to explain this phenomena
Atom will not stable
J.J. Thompson's :
Electrons embedded through out volume
A change from Newton's model of the atom as a tiny,hard,indestructible sphere
Bohr's theory of the hydrogen atom
Assumptions: The electron moves in circular orbits around the proton under the influence of the coulomb force of attraction.
Angular momentum
:
Centripetal force
:
Radiation:
emitted by the atom when the electron "jumps"
from allowed orbit to another allowed orbit
"jump" cannot be treated classically
frequency of radiation emitted in the "jump" is related to the charge in the energy of the electron
Ei-Ef=hf
Electron Energy:
Energy of electrons
Potential Energy:
Kinetic Energy:
Total Energy:
Hydrogen Energy Levels
E = -E0/n2, where E0 = 13.6 eV (1 eV = 1.602×10-19 Joules) and n = 1,2,3…
The hydrogen spectrum
Each line has a different wavelength and color
Formula
Erad=Ei-Ef
Erad=hf=hc/λ
Pauli's exclusion principle
No two electrons can have the same set of quantum number
Atomic spectra
At ordinary low temperatures, most of the atoms in a sample are in the ground state.
Only photons with energies equal to differences between energy levels can be absorbed/emitted.
X-rays
Electrons are emitted from a heated filament and accelerated through a large voltage
Higher orbital electrons then jump to occupy the vacant space
X-rays are emitted
Laser
High voltage applied causes electrons to sweep through the tube, producing excited states
Electron falls to E2 from E*3 in Ne, a 632.8nm photon is emitted
NUR ATIQAH FATEHAH BT MOHD AZHAN
AS10910
KULIAH 16
