does all light travel at the same velocity?
yes
speed of light units
c
3.00E8 ms-1
what is radiation measured in?
wavelength in meters and frequency in Hz or s-1
relationship between frequency and wavelength
wavelength x frequency = c
define amplitude
intensity of radiation, measure of strength of light
higher the frequency
the smaller the wavelength
what are quanta?
packets that energy come in
equations for photons, energy and frequency
energy = planks constant x frequency
energy = (planks constant x c)/wavelength
light has properties of….
quanta and waves
what is planks constant?
6.63e-34 J
passing light through a gas and then a prism:
- absorbing light at specific wavelengths causing darkness
excited gas emitting light:
- emitting light
absorption
electron absorbs energy and moves to a higher energy level
emmission
electron loses energy releasing energy as light
why does each element have a unique spectrum?
due to electrons
the value of each energy level for hydrogen (J)
energy of level = - (-2.18e-18 J)/energy level squared
what does energy do as an electron becomes more stable?
lowers
Rydberg equation
determines difference in energy as wavelengths between two shells
1/wavelength = 1.097e7 (1/n^2 - 1/n^2)
first energy level is the smaller one
wave-particle duality
sometimes electrons act as particles and sometimes like waves
so matter should exhibit wavelength properties
only really light things like electrons have detectable wavelength
- double slit experiment
what is the schrodinger equation for?
to make a statement about the probability of locating the electron based on the x,y and z axes - probability density
what are quantum numbers?
represent unique solutions to the schrodinger equation. there are 4 and each electron in an atom has a unique set
principle quantum number (n)
location of energy level eg n=4
angular momentum quantum number (l)
shape of the orbital. ranges from 0 to n-1.
orbital
an area where an electron is likely to be 95% of the time