quantum mechanics Flashcards
what is the rydberg equation?
v(frequency) = Rh [1/n (initial) ^2 - 1/n (final)^2 ]
what is the rydeberg equation used for?
to calculate the frequency of light when an electron moves form one orbital to another.
what does n (initial) equal in the Balmer series
2
what does n (initial) equal in the Paschen series
3
what does n (initial) equal in the Lyman series
1
what type of light is used for the Lyman series
ultra violet
what type of light is used for the Balmer series
visible
what type of light is used for the paschen series
infrared
what happens if you are able to fully remove an electron from an atom (move it up an infinite number of shells.)
the n (final) becomes infinity, any number over infinity is 0. (this is the same thing as ionisation energy.)
when the Rydberg equation to calculate the ionisation energy, the infinity should go _____ and the second value should be ______
first, stated in the question
what is the de Broglie equation?
wavelength = h/mv (velocity)
when would you use the de Broglie equation ?
when calculating the wavelength of a moving object
what does the Heisenberg uncertainty principle state ?
it is impossible to predict both the precise position and momentum of an object. - the more precise that we know the of the location, the more uncertain the momentum will become and vice versa.
what is the equation for the Heisenberg uncertainty principle?
delta p . delta q >= h/4pi
how do you calculate the change in momentum ?
since p=mv
delta = m . deltav
what element is the schrodinger equation used for and why?
hydrogen, as it only has 1 electron.
what does H^ stand for and what does it hold?
the Hamiltonian operator, and it holds all the info on the conditions of the atom.
what is the Schrödinger equation
H^ Y(wave function symbol) = E Y( wave function symbol)
what is the equation (linked to the Schrödinger equation), which helps us find the energy for the different hydrogen orbitals?
En = - hR/n^2
what is an orbital?
an orbital is the region of space defined by the wave function
what does the radial wavefuntion describe ? [R(r)]
the distance of an electron from the nucleus of an atom
what does R(r)^2 stand for
the radial probability density
what does the radial probability density show us ? [R(r)^2]
The probability of finding the electron at a point located distance r from the proton.
(This is important to use as a square number can never be negative. )
what is the equation for the radial distribution function?
4pi(r)^2R(r)^2
draw the graph of R(r) for a 1s orbital
exponential decay from 1
draw the graph of R(r) for a 2s orbital
exponential decay from 1 and a dip below the x axis.
draw the graph of R(r) for a 2p orbital
starting from 0 straight up to 1, then an exponential decay back to 0.
draw the graph of R(r) for a 3s orbital
exponential decay from, a dip below the x axis and a hump above the x axis.
draw the graph of R(r) for a 3p orbital
starting from 0 straight up to 1, then an exponential decay back to 0, with an dip below the x axis
draw the graph of R(r) for a 3d orbital
same as 2p, but a less steep line up to 1 from the origin.
what do the graphs look like for R(r)^2
in tetxbook
- s starts from 1
never drops below 0
draw the graphs for the radial distribution function against r
in textbook
- all start from origin
- extra waves are smaller before the big wave
- never drops below 0
when does a node exist?
where there is a 0% chance of finding an electron.
where R(r)=0
what helps you determine the number of radial nodes?
n - l - 1 = number of radial nodes
where there is no nodes there is ….
0 probability of finding an electron
what helps you determine the number of angular nodes?
It is equal to the value of l
draw the d xy orbital
in between the x and y axis
draw the d yz orbital
in between the z and y axis
draw the d xz orbital
inbetween the x and z axis
draw the x^2 - y^2 orbital
lies on the x and y axis
draw the z^2 orbital
p orbital along the z axis and a ring around the centre
what is the Pauli exclusion principle
No 2 electrons in the same atom can have the same 4 quantum numbers.
what is aufbaus principle
orbitals much be filled in order of increasing energy
what is hunds rule
When filling a set of degenerate orbitals, electrons are added with parallel spins to different orbitals.
for what elements is hunds rule broken
chromium and copper
what is the order of better shielding
s>p>d>f
how do you find the total nuclear charge on a nucleus
the number of protons
draw a 3p orbital
draw a Pz orbital
only side on one
strong s-p mixing occurs when s and p have ____
similar energies - elements bonding up to carbon is normally considered to have strong s-p mixing
why are 2s orbitals more penetrating than 2p orbitals?
(higher probability of finding an electron.)
The presence of the radial node of the 2s orbital mean sit has an area of high electron density close to the nucleus, which the 2p doesn’t.
The 2s electron is said to penetrate the 1s electron and thus the 2s electron feels higher effective nuclear charge than the 2p electron.
The 2s orbital is therefore more stabilised than the 2p orbital.
what does u mean
when the orbital is inverted it experiences a phase change.
