Transcript Chapter 4 Electron Configuration

Chapter 4
Electron Configuration
Radiant Energy
Electromagnetic radiation – all classes of
light
Includes: radio waves, T.V. waves,
microwaves, infrared, visible, U.V.,
X-ray, gamma ray
The wave carries both an electric field
and a magnetic field
A wave is its own opposite
http://www.science.uwaterloo.ca/~cchieh/c
act/c120/emwave.html
Waves can add or cancel,
http://academics.uww.edu/physics/courses
/physcs240/waveadd.html
Wave creation and absorption
If there is no physical process in a
substance that matches the frequency of
the wave, the substance will be
transparent to that wave.
Communication waves – electrons pulsing
back and forth along a wire
Visible and ultraviolet – electrons being
excited to higher energy levels
X-ray and gamma ray – breaking molecular
bonds and ionizing atoms
Methods of absorption are also methods of
creating waves.
Wave equation and units: λ = c/ ν
λ (lambda) is wavelength
c is the speed of light (3 x 108 m/sec)
ν (nu) is frequency in waves/sec or cycles/sec
Quantum Theory
There is a lowest packet of energy (a
quantum) associated with each frequency
of light
The higher the frequency, the more the
packet (quantum) contains
E = hν
E is energy in joules
h is Plank’s constant (6.62 x 10-34 J sec
ν is frequency
The photoelectric effect
A high energy beam of red light will not
emit electrons from sodium metal while a
dim beam of violet light will.
http://hyperphysics.phyastr.gsu.edu/hbase/mod1.html#c5
If the packet of energy (photon, quantum)
is not equal to or greater than the
difference between two electron orbitals
the energy will not be absorbed.
Another look at the atom
Note the flame colors on page 135.
These colors (amounts of energy)
correspond to energy given off or
absorbed as an electron goes from one
energy level to another.
See the top of page 137 (excited and
ground energy levels)
The wave nature of matter
Very small particles (such as electrons)
exhibit wave properties such as wave
addition and cancellation.
The smaller the particle, the longer the
wavelength.
The De Broglie wave equation for
an atom
Standing wave
http://id.mind.net/~zona/mstm/physics/waves/sta
ndingWaves/standingWaves1/StandingWaves1.
html
Standing wave of an electron around an atom
http://www2.kutl.kyushuu.ac.jp/seminar/MicroWorld1_E/Part4_E/P44_E/
wave_character_of_electron_E.htm
The De Broglie wave equation is based on the
idea that the mean orbital path should be 1, 2,
3, etc. wavelengths long.
See orbital shapes on page 144 and 145
See electron filling order chart (on board)
Pauli exclusion principle – no more than 2
electrons can occupy one orbital
Hund’s Rule – p orbitals will all fill with one
electron before they start to fill with 2.
d and f orbitals also fill with one electron
first