Quantum Theory Flashcards
Spectroscopy
The method for finding out about the structure of molecules that depends on the interaction of molecular compounds with radiation.
Absorption Spectrum
A plot of radiation energy versus the percentage of radiation transmitted
Frequency
“nu” - the number of wave peaks that pass by a fixed point per until time.
Wavenumber
The number of repeating units of a wave in a unit of space (rather than time). This is a reciprocal of frequency.
What happens when molecules absorb microwaves?
Molecular tumbling
What happens when molecules absorb ultraviolet light?
Covalent bonds can rupture
What happens when molecules absorb infrared light?
Molecular vibration
How do atoms become excited?
Atoms absorb energy.
How do atoms return to their ground state?
Atoms release their extra energy by emission of radiation.
Line Emission Spectrum
Excited atoms emit only particular wavelengths of light - when this light is passed through a prism, only a few coloured lines are seen.
What does it mean for the energy of electrons to be quantized?
They can only have particular amounts of energy and not values between the “allowed” levels.
Lyman Series
A series of emission lines having energies in the ultraviolet region.
Balme Series
A series of emission lines have energies in the visible region.
What is the l value for the s orbital?
0
What is the l value for the p orbital?
1
What is the l value for the d orbital?
2
What is the l value for the f orbital?
3
What orbital has the l value of 0?
s orbital
What orbital has the l value of 1?
p orbital
What orbital has the l value of 2?
d orbital
What orbital has the l value of 3?
f orbital
What is an orbital?
Refers to a mathematical function, which is one part of the solution to the wave equation for each stationary wave. Non-uniform distributions of electron matter over space around the nucleus.
Orbitals of an atom that have been derived by use of the same value of n in the Schrodinger equation are said to be in the same _____.
Shell
Example: The 2s orbital (n=2, l=0) and the three 2p orbitals (n=2, l=1) are all part of the same n=2 shell.
In a given shell, each set of orbitals derived by use of a particular value of l in the Schrodinger equation are said to be in the same ________.
Sub-shell
Example: in the n=3 shell, the 3s subshell is comprised of the 3s orbital (l=0,m1 =0)
What type of wave is an electron?
A standing wave
How can you find the number of orbitals in a sub-shell?
2(L) + 1
How many orbitals in sub-shell s?
1
How many orbitals in sub-shell p?
3
How many orbitals in sub-shell d?
5
How many orbitals in sub-shell f?
7
Diamagnetic
Substances that are slightly repelled by a magnet
Paramagnetic
Substances that are attracted to a magnetic field. They have unpaired electrons.
What is the shape of s orbitals?
They are spherically symmetrical.
Principal QN n
n = 1,2,3…
How do you find the density of the electron wave?
Wavefunction^2
As the principal QN n increases, the number of nodes in a wavefunction ____________.
increases
At a node, the sign of the wavefunction is _______.
zero
On either side of a node, the sign of the wavefunction __________.
changes phase
A node is a region of _______ electron density.
zero
Radial node
a region of zero electron density that exists at a specific radial distance from the nucleus. In 3D a radial node is a sphere, but a 2D cross section represents such a node as a circle.
Angular Node
a plane of zero electron density that exists at a specific angle from a particular axis. In 3D, a angular node is a plane, but 2D cross section represents such a node as a line
The total number of nodes depends on principal QN n, and is equal to _____.
n-1
As the principal quantum number increases, the orbital size ___________.
increases
In an s-orbital, the angular QN, l, is always equal to______.
zero
In an s-orbital, the number of angular nodes is always equal to ______.
zero
In a p-orbital, the angular QN, l, is always equal to ____.
one
In a p-orbital, the number of angular nodes is always equal to ____.
one
In both s and p orbitals, the number of angular nodes equals _____.
l
The number of angular nodes in a d-orbital is always equal to _______.
two
The value of the principal QN n determines the number of _________ nodes.
total
The value of the principal QN n determines the ______ of the orbital.
size
The value of the angular QN l determines the number of ________ nodes.
angular
The value of the angular QN l determines the ______ of the orbitals.
shape
How do you find the energy of an electron at a certain energy state?
Equation: E = -(1/n^2)RH
What is the equation for wavelength of a photon?
“lambda” = hc/E
What is the equation for wavelength of a particle?
“lambda” = h/mv
How many atomic orbitals are in the sub-shell with quantum numbers n = 6 and l =2?
Five. This is a 6d orbital. All d orbitals have 5 orbitals.
