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