Symbol for wavelength?
Speed of light?
3.00 x 108 m/s
Relationship between wavelength and frequency?
c = (wavelength)(frequency)
EM Radiation Experiments? (hint: 3)
- - Blackbody Radiation
- - Photoelectric Effect
- - Emmission Spectrum of gases
- ~ EM Radiation comes from objects that have been heated
- ~ high frequency, (short wavelength) has a high energy
- - the inverse is also true -
Planck's Constant (h)
6.626 x 10-34 J*s
- tiny packets of light, photons, have own unique energy
- Ephoton = hv
- photons behave like particles and like waves (duality)
Emission Spectrum of Gases?
- Excited atoms emit light at discrete wavelengths
- every atom gives unique emission spectrum
- E = hc/lambda
principle quantum number n
- "orbits" of specific size where the energy of the electrons depends on n
- lower n = lower E and the orbit is closer to the nucleus
what causes the "lines" in emission spectra?
- When an electron falls back to the ground state from an excited state the E emitted as a quantum of light, or photon.
- this photon represents the "lines".
The amount of E absorbed or emitted in promoting or demoting electrons within allowed n levels
Change in E = Ef - Ei = [(-RH/n2f) - (-RH/n2i)]
RH = 2.18 x 10-18J
Based on the equation, if the change in E is less than 0 and E is given off this is an
Based on the equation, if the change in E is greater than 0 and E is absorbed this is an
Based on the equation, if the final energy level is infinity, the electron has been removed completely
What is the relationship between mass and wavelength?
wavelength = h/mass x velocity
Heisenberg's Uncertainty Principle
uncertainty in position x energy (or momentum) is greater than or equal to h/4 pie
the mathematical equation that describes the electrons
Angular Momentum Quantum Number (l)
- defines the shape of the orbital
- range from 0 to n-1
- we use letter designations in place of l