Atomic Theory Chapter 12 Flashcards
Wavelength(w)
Distance between the adjacent crest of a wave (in m )
Frequency(v)
The number of crests passing through a given point per second (in Hz or s^-1)
Speed of light (c)
speed of the movement in a given crest
Constant value is: 2.988 x10^8 m/s
Formula for Sped of light
c= v(w)
Amplitude
Max height of the wave above centerline
Constructive interference
When a crest of a wave meets another crest of another wave the amplitude of the waves add together.
Destructive interference
a crest of a wave meets a trough of another wave, the two waves cancel each other out
Black body radiation Part 1
All non-reflective objects (black-bodies ) emit light (black body radiation).
- Black body room temperature appears black as most of the energy it emits is Infared
- A heated metal emits visible light
- Temp becomes higher, the color of emitted light shifts from red to blue
Photons
They are a stream of particles that light is made up of and has energy
Plank’s equation
E photon = hv = hc/ w
Plank’s constant
h = 6.626 x 10^-34 Js
Law of conservation of Energy
Ei + hv = Ef
Electron circular orbits formula
En = - Z^2 (RH)/ n^2
Rh constant
2.179 x 10^-18
Z
atomic number
Law of conservation of energy
Eph= hv= Ef-Ei
Black body radiation part 2
- Spectrum of black body radiation is peaked at a characteristic frequency that shifts to shorter wavelength with increasing temperature
Higher temp = shorter wavelength - Classical theory falsely predicts that intensity would increase indefinitely with decreasing wavelength
Energy of light with frequency v
Is quantized because energy must be an integer multiple of the photon energy.
Different measurements of wavelength least to greatest
pm<nm<mm<m of wavelength
Electromagnetic radiation
Eletric and magnetic fields propagate as waves through a vacuum or through a medium.
why is energy of light with frequency(v) is quantized
Energy must be the integer multiples of the photon energy.
Emission
is the way in which excited atoms emit energy as photons to relax to lower energy levels.
emission spectra of atoms
discontinuous
absorption spectra of atoms are
discontinuous