It’s not about Dalton anymore…
To understand the electronic structure of the atom we need to review the properties of electromagnetic radiation.
Frequency and Wavelength
c = l n
l = wavelength
n = frequency
C = speed of light
The Wave Nature
The waveheight or amplitude determines radiation intensity.
The wavelength is related to the energy of the radiation.
λ, ν, and Energy
As λ decreases and ν increases, what happened to the energy of the radiation?
where h = Planck’s constant
(6.626 × 10-34 m2 kg/s)
Regions of the electromagnetic spectrum.
The infinite number of wavelengths of
electromagnetic radiation have been classified
into groups as shown below.
Interconverting Wavelength and Frequency
Use c = ln
= 1.00x10-10 m
= 325x10-2 m
= 473x10-9 m
= 3x1018 s-1
= 9.23x107 s-1
= 6.34x1014 s-1
Calculating the Energy of Radiation from Its Wavelength
After converting cm to m, we can use the energy equation, E = hn combined with n = c/l to find the energy.
E = hc/l
Different behaviors of waves and particles.
The diffraction pattern caused by light
passing through two adjacent slits.
Light falling on alkali metals causes electrons to be released from the metal.
The # of electrons depends on the intensity of light.
There are specific wavelengths of light that cause the release of e-.
This is called the photoelectric effect.