Week 2 - Intro Quantum II Flashcards
The higher the energy level…
the further from the nucleus the orbit is.
What must an atom do to change to another stationary state (electron moves to another orbit)?
Absorb or emit a photon
In the equation E = ΔE = E(f) - E(i), what does each part mean?
E = energy of photon
ΔE = change in energy
E(f), E(i)= final and initial orbit energy
What does the value ‘n’ tell us about the electron in an atom?
- Distance from the nucleus
- Energy
Ground state vs excited state
GS: when an electron is in the first orbit (n=1) closest to the nucleus
ES: electron is in any other orbit
Electron absorption
if an electron absorbs a photon whose energy equals the difference between lower and higher energy levels, the electron moves to the outer (higher energy) level
Electron emission
If an electron goes from a higher to a lower energy level, the atom emits a photon whose energy equals the difference between the two levels (typically or always going to ground state, n=1)
In the equation E = -2.18x10^-18 ((Z^2)/(n^2)), what does each part mean?
E = energy of an electron in orbit ‘n’
number = Bohr’s Constant
Z = atomic number (H=1,He=2…)
n = orbit number
Which atoms does Bohr’s model explain the spectra for?
Hydrogen and other 1-electron species (cannot be used for multi-electron species)
Which energy difference between orbitals is the largest?
n = 1 to n = 2
Which range do emissions to the first three orbits fall into?
Emissions to n=1 are UV
Emissions to n=2 are visible
Emissions to n=3 are infrared
What do matter and light have in common?
Both have wavelengths
In the equation (λ = h/mu), what does each part mean and what is this equation used for?
λ = wavelength
h = Planck’s constant
m = mass
u = velocity
Used for calculating wavelength of matter (De Broglie’s principle)
In the equation ΔxΔp≥h/4𝝅, what does each part mean and what is this principle?
Δx = uncertainty in position
Δp = uncertainty in momentum
h = Planck’s constant
This is Heisenberg’s Uncertainty Principle
Precision of position and momentum have an ______ relation
Inverse
i.e. if the position of a particle can be determined more precisely, then the momentum of the particle is predicted less precisely. You cannot determine both precisely.
Schrodinger described electron distribution as a…
standing wave
Each wavefunction is defined by what three quantum numbers?
n, l, and m
What do we get if we square the wave function (Ψ)?
The probability of finding an electron at a given point
Orbitals are…
mathematically derived regions of space with different probabilities of containing an electron
Describe the principal quantum number, n
- positive integer (1,2,3…)
- indicates size of orbital
- specifies energy level
Describe the angular quantum number, l
- positive integer (0 to n-1)
- shape of orbital
- value of n limits l
when l=0, s orbital
when l=1, p orbital
when l=2, d orbital
when l=3, f orbital
Describe the magnetic quantum number, m(l)
- integer (-l to +l)
- orientation of the orbital around the nucleus
- value of l limits m(l); if l=1, m(l) can be -1,0,1
Shape of s-2s orbital? Value of l?
Spherical, l=0
Shape of p-2p orbital? l value?
Dumbbell shaped (two circles), l=1
Electron probability density is highest at…
r = 0; closer to the nucleus
What are nodes?
Regions where there is no probability of finding an electron
What is a radial node? How do you determine how many an orbital has?
In s orbitals, radial nodes depend on quantum numbers n and l; located at n-1-l
What is an angular node? How do you determine how many an orbital has?
In p orbitals, angular nodes depend on quantum number l; they are equal to l
Describe the n/l table for determining orbital.
l across the top, going from 0 to 2
n along the left, from 1 to 4
n values determine number (same)
l values determine letter:0=s,1=p,2=d
How do you determine radial/angular nodes?
Radial = n-1-l
Angular = l
What is N subscript A?
the number of photons in one mol of photons; Avogadro’s number
What does n^2 give you?
The number of orbitals with that n as their principal quantum number
Formulas to calculate momentum of a proton
p = h/λ, p = mu, p = E/c
