Why are electrons restricted to specific energy levels or quantized? Louis de Broglie – proposed...
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Transcript of Why are electrons restricted to specific energy levels or quantized? Louis de Broglie – proposed...
Why are electrons restricted to specific energy levels or quantized?
Louis de Broglie – proposed that if waves have particle properties, possible particles have wave properties.This includes such things as nodes:
• Relationship between wave properties (wavelength) and particles (mass*volume)
• De Broglie equation λ = h / mu
wavelength, planks, mass, velocity
Problem on Page 260
• Calculate the wavelength of a H atom, mass = 1.674 x 10 -27kg moving at 700 cm/s
Quantum Mechanics
Heisenberg Uncertainty Principle – It is not possible to know simultaneously both the momentum p (mass x velocity) and the position of a particle with certainty
This is due to the measurement methods moving the electron
Quantum Mechanics
• ΔxΔp ≥ h / 4π • If our measurement of the momentum p is
increased, knowledge of position decreases
• If the measure of position x is known more precise, the momentum measurement is decreased
• One problem is due to the electrons not following circular paths like planets.
Schrödinger Equation
• This works fair for the Hydrogen atom
• We approximate multi electron atoms
Quantum Numbers
n – principle quantum number
Energy level of an orbital = 1, 2, 3…
Quantum Numbers
l – Angular momentum number (Orbital)
l = n-1 0-s 1-p 2-d 3-f
Quantum Numbers
• ml – Magnetic Quantum number • the number of them = (2l + 1), • If l = 0 then ml = is 0 • If l = 1 then ml = 1,0,-1 ; • Describes the orientation in space x y z
Quantum Numbers
Ms –electron spin quantum number
= ½ or –½
Quantum Numbers
Ms –electron spin quantum number
= ½ or –½