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 act/c120/emwave.html act/c120/emwave.html Waves can add or cancel, /physcs240/waveadd.html /physcs240/waveadd.html /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 10 8 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 = hν E is energy in joules E is energy in joules h is Plank’s constant (6.62 x sec h is Plank’s constant (6.62 x J sec ν is frequency 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. astr.gsu.edu/hbase/mod1.html#c5 astr.gsu.edu/hbase/mod1.html#c5 astr.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 the energy will not be absorbed. 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 ndingWaves/standingWaves1/StandingWaves1. html ndingWaves/standingWaves1/StandingWaves1. html ndingWaves/standingWaves1/StandingWaves1. html Standing wave of an electron around an atom u.ac.jp/seminar/MicroWorld1_E/Part4_E/P44_E/ wave_character_of_electron_E.htm u.ac.jp/seminar/MicroWorld1_E/Part4_E/P44_E/ wave_character_of_electron_E.htm u.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 d and f orbitals also fill with one electron first