Atomic Theory Flashcards
Electromagnetic Waves
Oscillations of an EM field that propagate through space at the speed of light
Wavelength Definition
Distance between 2 points of an EM wave (nm)
Frequency Definition
Number of oscillation cycles that occur at a fixed point in one second (s)
Longer wavelengths imply ____ frequency (lower/higher)
Lower
Shorter wavelengths imply ___ frequency (lower/higher)
Higher
Amplitude Definition
“height” of a wave from the midpoint
Amplitude squared gives the ___
Wave intensity
Wavelength and frequency have a ______ relationship
Inverse
Balmer Series is for what radiation
Visible color rays
Lyman Series is for what radiation
UV rays
Paschan Series is for what radiation
Infrared rays
Rydberg Series
R0
What does the Rydberg Equation do?
Return wavelength regions as energy integers, helping Bohr
What is the relationship between wave amplitude and light intensity?
Higher amplitude = higher brightness
What is the only characteristic that distinguishes one form of electromagnetic radiation from another?
Wavelength
As wavelength increases, energy levels become ______ (lower/higher)
Lower
As frequency increases, energy levels become _______ (lower/higher)
Higher
Lowest-energy EM radiation?
Radio rays
Highest-energy EM radiation
Gamma rays
Formula to calculate total energy of a photon? (E=hv or E=hc/lambda)
Plancks constant x frequency or Plancks constant x the speed of light/wavelength
Photons from light behave as __________
waves or small particles
Energy from a light can be absorbed or emitted only as
individual small photons
As the energy level of an orbit increases, how does the energy difference change?
Energy difference between consecutive levels decreases
What happens when an excited hydrogen atom returns to a lower energy level orbit?
The atom releases a photon with wavelength that corresponds to the energy difference between the two levels involved
What is constructive interference
When two interacting waves are in phase, (max and min are aligned), resulting in a wave that is the sum of both waves
What is destructive interference
when two waves are in opposite phases, creating a wave with zero amplitude, cancelling each other out
In the two-slit experiment, after diffraction, waves in phase were ___ (dark/bright)
Bright
In the two-slit experiement, after diffraction, waves out of phase were ___ (dark/bright)
Dark
What was wrong with Bohr’s Theory (4 points)
- Didn’t explain why electrons don’t fall onto the nucleus
- Didn’t explain why only some wavelengths were allowed
- Upon inspection, energy levels were split into two lines, unclear why
- The model doesnt work for other elements aside from hydrogen
What was the key difference between Bohr and deBroglie’s quantums
Electrons are particles with WAVE properties
What equation provides the principal quantum number (n) and what is the purpose of “n”
of nodes + 1 = n, describes wave function type (1-4)
More nodes = (more/less) energy
More
How does a guitar conceptually demonstrate waves
Guitars have STANDING waves, when amplitude is affected, higher notes are returned
Define orbitals
wavefunctions of individual electrons with shapes/sizes that predict the probability of finding an electron within
What is the azimuthal (l) quantum number?
l = n-1, describes orbital type and shape (spdf)
What is the magnetic (m1) quantum number?
m1= -l to +l, describes orientation: s=0, p= -1 to +1, d=-3 to +3 etc
What is the Ms quantum number?
Spin quantum for describing 2 electrons in the same orbital, could be up or down
Where is the highest density of electrons most likely to be found near?
The middle of the atom
Is there ever a negative possibility of finding an electron
No
Pauli’s Exclusion Principle
No 2 electrons can have the same 4 quantum numbers
Electron in an Excited state
An electron can become excited if it is given extra energy, such as if it absorbs a photon
Hund’s rule
all orbitals will be singly occupied before any is doubly occupied
Aufbau’s Rule
electrons fill subshells of the lowest available energy, then they fill subshells of higher energy. For example, the 1s subshell is filled before the 2s subshell is occupied
How does the speed of light change for wavelengths in different orbitals
It doesn’t, all of c is the same in a vacuum
Electron vs standing waves similarities (3)
Both undergo constructive interference, nodes and increase in energy with # of nodes
Schrodingers Equation
Gives the wavefunction and associated energy of an electron to describe orbitals
Shape of s orbital
spherical, # of colors indicate # of nodes
Shape of p orbital
perpendicular axes, xy, xz, yz
Shape of d orbital
Four clovers and one inside out cone donut, x^2y^2, xy, xz, zy, z^2
Principle number (n) function
of nodes, describes energy and size
bohr’s model
coorelates each group of spectral lines to a wavelength of EM radtion, and determined that when H+ electrons absorb energy they become excited
Node
point where wavelength = 0, no electron probability, changing phases
Why do orbital drawings use multiple colors
shows orbitals above and below nodes
What does degenerate mean with the magnetic quantum number
determines orientation in xyz but all are the same energy
pnictogens
group 15
Em-En
Ephoton
