Topic 1- Lecture 2 Flashcards
The number of times a wave repeats itself per second
Frequency
ν
Linear distance a wave covers before repeating itself
Wavelength
λ
C=λν
Speed of light= wavelength X frequency
3.00 x 10^8 m/s
Short wavelength=
Large frequency
Long wavelength=
Small frequency
The height of each step is equal to one quantum of energy for a certain frequency electromagnetic radiation.
Quantum Theory
Max Planck
E=hν
Quantum Theory
E=energy per quantum
h= Planck’s constant (6.63x10^-34)
ν= frequency
- Highly intense low frequency light does not eject any electrons
- When threshold frequency is reached, electrons are ejected immediately
- Increasing the intensity of light that ejects electrons causes electrons to be ejected at a greater rate and velocity, but all electrons share the same velocity
Photoelectric effect
A beam of light is a stream of particles called…
Photons
Einstein
A photon is equal to a…
Quantum
Einstein
If the frequency of a photon is below a certain threshold, no…
Electrons are ejected
Einstein
If the frequency of the photon is at or above a certain threshold, it’s energy is transferred…
To the electron
Energy increases as…
Frequency increases
Einstein and Planck
Forces of attraction between the electrons and the nucleus result from…
Opposite charges
The force of attraction decreases as the distance between the outermost electron and the proton increases.
Coulomb’s Law
- Electrons move around nucleus in circular orbits
- Each orbit is a fixed distance from nucleus
- Electrons within an orbit have set, quantized, energy levels
Bohr Model
Electrons that are furthest from the nucleus are partly “blocked” by the inner core electrons
Shielding effect
-reduces electrostatic attractions
The minimum amount of energy needed to remove the outermost, least tightly held, electron from an atom
First Ionization Energy
Low ionization to high ionization across the periodic table
Increases left to right
Ionization data suggests that electrons are arranged in shells
Shell Model
N=1
2 electrons
N=2
8 electrons
Electrons contained in inner shell(s)
Inner core electrons
Electrons contained in outer shell
Valence electrons
1s
2 electrons
2s
2 electrons
2p
6 electrons
3s
2 electrons
3p
6 electrons
3d
10 electrons
Ionization energy decreases due to an increase in the…
Shielding effect
