Energy propagated by energetic and magnetic field that increases and then increases in intensity?
electromagnetic radiation
How is electromagnetic radiation described/
by a wave model
What is the wavelength?
What is it represented by?
What is it usually measured in?
distance between the crests of waves
ƛ
nm
What is the frequency?
What is it represented by?
What is it usually measured in?
cycles per second
Greek letter nu (𝜈)
Hertz (Hz) [s^-1]
Relationship between wavelength and frequency?
wavelength increases
frequency decreases
When does the wavelength get more harmful?
the lower it is the more harmful
What is the velocity?
What is it represented by?
What is it usually measured in?
distance a wave can travel per unit time
v
m/s
What is the speed of light?
c = 3.00 x10^8 m/s
What is the equation for velocity?
v = ƛ𝜈
What is the amplitude?
What is it represented by?
What is it usually measured in?
height of crests, depth of troughs
A?
meters
What is amplitude related to?
intensity
What is the relationship between amplitude and intensity/
Amplitude increase, then Intensity increase
What does intensity depend on?
different colors
What causes a change in amplitude?
change in intensity
What is an example of refraction?
rainbows
What is an example of diffraction?
awarenesses that a flashlight is on
Waves travel at different speeds through different media, the transition causes a change in direction?
refraction
Does matter refract or diffract like energy does?
no
Waves bend around the edges of an object?
diffraction
What is blackbody radiation?
an object emitting light when it is heated
As heat is increased to an object, what happens/
the light changes color
What relation does the blackbody radiation show/
relationship between heat & light intensity/wavelength (ƛ)
Who takes the first steps of quantum theory and what did he say?
max planck
objects emit only certain quantities of energy
What equation did plank come up with?
E = nh𝜈
What does each letter stand for in the equation E = nh𝜈 ?
E = energy of radiation
n = the quantum number (positive integer)
h = planks constant
𝜈 = frequency
What is planks contant?
h = 6.626 x10^-34 J x s
What are four major points of planck reasoning?
- objects emit certain quantities of energy
- energy must be emitted by atoms
- atoms must only have certain quantity of energy available to it
- an atoms energy must be quantized
What does quantized mean/
occurring in fixed quantities
When does an atoms energy change?
when it emits or absorbs a quantum
What is the equation for ΔE ?
ΔE = Δ energy absorbed/emitted
ΔE = Δnh𝜈
What is the formula for the smallest possible change in energy?
ΔE = h𝜈
When monochromic light (single wavelength) of a sufficient frequency strikes a metal plate, a current flows with out a time lag?
the photoelectric effect
With the photoelectric effect, for current to flow what must occur?
sufficient frequency
no time lag
What does the threshold frequency change with?
different metals
What is the minimum frequency of light a current requires called?
threshold frequency
What does the classical model of light associate energy with?
associates energy with amplitude instead of frequency
What is the no time lag?
the current flows the moment the light strikes the metal surface
What did Albert Einstein say about light and energy?
light is quantized into bundles of energy
What are the bundles of energy light is quantized into called?
photons
What happens to photons when energy changes?
a photon is absorbed or emitted
What is the E of a photon?
Who said this?
E (photon) = h𝜈 = ΔE (atom)
Albert Einstein
What is the energy of atoms and photons related to and not related to?
related to frequency
not to amplitude
How can an electron not be ejected from the metal by ?
by storying energy from multiple photons
What is the relationship between wavelength and energy?
wavelength decreases, then
energy increases
Scientists saw unique lines across other sections of the electromagnetic spectrum….Who came up with an equation for it?
Johannes Rydberg
1888
What was Rydberg’s equations?
What elements did it work for?
(1/ƛ) = R(H) [(1/n2a) - (1/n2b)]
only H
In Rydberg’s equation what must n be?
n must be an integer
n(a) < n(b)
What is R(H)?
Rydberg’s constant for H
R(H) = 1.096776 x10^7 m^-1
Who made the Bohr model?
Niels Bohr
1915
What was the Bohr model combined ideas of?
planck, einstein, and rydberg
What is the ΔE ?
E final - E initial
What does the Bohr model perfectly define but nothing else?
Hydrogen
What are the 3 ideas of the Bohr model?
- H only has stationary states: only certain energy levels
Each state associated with a fixed circular electron orbit around nucleus.
Higher energy level = Farther from nucleus - Atom in stationary state = no energy radiated
Atom doesn’t not change energy within orbit. - Electron moving to another orbit / atom changing energy state only occurs by absorbing/emitting a photon
What are the five features of the Bohr model?
- quantum numbers and electron orbit
- ground state
- excited state
- absorption
- emission
The number that describes the state of an atom?
quantum number
Distribution of e- that puts an atom at its lowest energy ?
ground state
Distribution where 1 or more electrons move into a higher state so its not at its lowest energy?
excited state
What does the Bohr model only predict?
the line spectra for only H atom
- b/c its a one electron model
What is another issue with the Bohr model other than only working for H?
electrons do not move in fixed orbitals
What do we still use today from the Bohr model?
idea of discrete energy levels
ground state / excited state terms
energy change is related to absorption/emission of specific photon energies
What is a positive change in energy?
going from lower energy state to higher
an atom is absorbing a photon
What is a negative change in energy?
going from lower energy state to higher
an atom is emitting a photon
What did Bohr do and not have for his model?
fit theory to data
no basis for assumption
had no hypothesis
Who studied fixed motion of a wavelength with a guitar string?
Louis de Broglie
What was the big question that formed from Louis de Broglie’s research?
if energy can behave like particles,
why can matter not behave like a wave
What is the formula for harmonics?
L = n (ƛ/2)
What ideas does de Broglie use to form an equation?
What is the equation?
planck and einstein
ƛ = h / (m x u)
What do these variables mean?
u =
v =
c =
speed of the electron
speed
speed of light
What is one J ?
(1 kg x m^2) / s^2
When will waves diffract around a slit or opening?
if the opening is on a similar scale to the wavelength of the light
Who studied and made conclusion about x rays , wavelength, and crystalline materials?
Clinton Davisson
Lester Germer
1927
What was said about the X-ray and wavelengths studied with crystalline?
x-ray wavelength
space between atoms in certain crystals
electron wavelength
What does this mean ?
x ray ƛ = 10^-10
crystals ƛ = 10^-10
electron ƛ = 7.27 x10^-10
electrons have a wavelength b/c diffracted
What did Davisson and Germer see with the electron?
it made a pattern but not the same as the xray
** it has a wavelength
What is momentum?
product of speed and mass
the smaller the wavelength, the higher the ____and _____
energy
momentum
What is the equation for momentum?
p = h/ƛ
What happens when 2 things collide with different momentums/
they separate with the same momentums
* momentum is conserved
What did Arthur Compton say?
1923
wavelength of light changes when its collided with an electron
Who used theory to explain observation?
Who used observation to explain theory?
Planck, Einstein, and Bohr
Davisson, Germer, and Compton
What exhibits both particle like and wavelike behavior/
matter and energy
Who came up with the theory of relativity?
Albert einstein
1905
What is the theory of relativity?
What is the equation?
matter and energy are alternate forms of the same entity
E=mc^2
Who came up with he uncertainty principle?
Werner Heisenberg
1927
What is the uncertainty principle ?
it is impossible to know with certainty both the location and the speed of an electron
What is the formula for uncertainty?
(ΔX)(mΔu) ≥ (h)/(4𝞹)
Δ = uncertainty (not change)
^^^ eq says minimus amount error
The Quantum Mechanics Atomic Model…
focuses on examining the ______ nature of objects on the atomic scale
describes an atom with specific quantities of _____ that result from allowed frequencies in an ____wave behavior
an electrons position can only be known with a certain probability
wave-like
energy
electron
What did Schrödinger say about electrons and space near the nucleus?
the electrons matter-wave occupies space near the nucleus and is influenced by it
What was Schrödinger equation ?
Erwin Schrödinger
*only need to understand
Ĥψ = Eψ
What is Ĥ?
What is ψ?
What is E?
hamiltonian operator
wave function
total energy of the electron
What does a wavefunction solution to the Schrödinger equation describe?
describes an orbital
Each dependable wavelength with the Schrödinger equation depend on a series of variables called what?
quantum numbers
What are the quantum numbers?
What do they describe?
n
ℓ
mℓ
an atomic orbital
What is the QN n?
What numbers are included?
What does it indicate?
a higher value = a ____ energy level
principle QN
positive integer (1, 2, 3…)
size
higher
What is the QN ℓ?
What numbers are included?
What does it indicate?
angular momentum QN
integer from 0 to (n-1)
shape
What is the QN mℓ?
What numbers are included?
What does it indicate?
magnetic QN
integer from -ℓ to +ℓ
orientation
What do we use to describe energy states and orbitals?
wave function and the QN associated
Describing a atom…
What is the n value?
What is the ℓ value?
What is the mℓ value?
shells
subshells
s: ℓ=0
p: ℓ=1
d: ℓ=2
f: ℓ=3
orbitals
How are QN used to write and stuuufff?
nℓ (subscripted mℓ)
What is the meaning?
ψ
ψ^2
no meaning
the probability density
What does ψ^2 describe?
What can we turn it into?
the physical location that an electron can possibly occupy
a 3D shape
What is the shape of the s orbital?
sphere
bigger n = bigger sphere
nodes (n-1)
What is the shape of the p orbital?
Bean / Bowtie shape
bigger n = bigger sphere
3 p orbitals (x, y, and z)
What is the shape of the d orbital?
butterfly
the fifth looks like a p orbital with a circle in the middle
For the H atom…
___ is the only QN to impact the energy of the orbital
the energy of all four n=___ orbitals are equal
- 2s
- 2p(x)
- 2p(y)
- 2p(z)
*only for H
principle QN
n=2
What can Schrödinger equation reveal?
- difficulties arise when there is ____
- the equation becomes___
- requires sophisticated _____
the total energy of an electron in an atom
more than one electron
unsolvable
approximations
What were the additions to the quantum model?
another quantum number
limit to electrons in an orbital
splitting on energy levels
What was the QN added?
What is that QN?
What numbers are included?
What does it indicate?
ms (s is subscript)
spin quantum number
2 possible: +1/2 , -1/2
the direction of spin
What do all four QN describe together?
the spin and the orbital
Who made the exclusion principle?
What did this person observe to form this principle?
Wolfgang
1925
excited states of helium
What are the two main points of the exclusion principle?
- no 2 electrons can have the same exact 4 QN’s in a single atom
- an atomic orbital can only hold 2 electrons, each with opposite spins
What is electrostatistics?
In H, all orbitals with an equal___ have equal ___
In other atoms, energy is based on what?
various effects of interacting charges cause a splitting of energy levels
n, energy
n and ℓ
What is it called when electrons repulse each other counter acting nuclear charge?
shielding
Is it easier to remove an electron with a more or less shielding?
why?
more
effective nuclear charge (Zeff) is reduced
What is Zeff or effective nuclear charge?
What is nuclear charge?
what charge an atom feels
what charge is actually there
Do higher or lower nuclear charges interact more strongly?
higher
Nuclear charge…
a more positive nucleus creates a stronger attraction to the electron, which does what to the overall energy?
lowers the energy
What are the two kinds of shielding ?
- same energy level electrons
- multiple electrons decrease stability - electrons in inner energy levels
- inner electrons block those in outer levels
What is electrical penetration?
what is it based on?
how close to nucleus
based on orbital shapes and radial probability
decreased ℓ = decreased E
What is the nuclear charge and shielding for 2s?
increased nuclear charge (over 2p) decreased shielding (by 1s)
What causes there be general trends for sub levels?
shielding and penetration
What happens to the shielding and penetration…when ℓ is smaller?
What is the sub shell order for energy?
greater penetrations
lower shielding
s < p < d < f
What are two examples of quantum mechanics providing theoretical explanations for experimentally based periodic table?
- electron assignments
- electron distributions in shells and sub shells - ground state electron configurations
- lowest energy distribution of electrons
What is the Aufbau Principle?
Starting at the beginning of the periodic table…
add 1 electron to the next lowest energy sub shell for each atom.
What are the two ways to represent the subshells using the Aufbau Principle ?
- electron configuration
- shorthand designations for energy level
- nℓ^# - orbital diagram
- represents orbital and spin
- up and down arrow for spin
What is the order you fill the sub shells?
1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p
