MARY - Topic 4 Flashcards
What is the Schrödinger wave equation used for?
To determine energy levels for electrons. It uses the idea of an electron acting as a wave that alters with position.
What is a wavefunction?
A mathematical function which varies with position. Each different wavefunction describes a different orbital type with a characteristic energy.
What do the different parts of the equation mean?
1 = KE of wavefunction 2 = Potential Energy
= E(Total) for electron @ point x,y,z in space.
What can the Schrödinger wave equation be solved for?
Only 1-electron systems, where it gives all the energy levels possible for that electron.
What is the wavefunction squared/the probability per unit volume?
The probability of an electron being in a certain volume of space.
What are the different quantum numbers?
n = Principal Quantum Number (determines the energy shell) l = Secondary Quantum Number (gives the types of orbitals possible for a given 'n') ml = Magnetic Quantum Number (orbital orientations for each l value)
What are the spherical (polar) coordinates?
(r, θ, φ ) = in radian units
1 = distance from nucleus 2 = deviation from the z axis 3 = deviation from x axis.
What can the wavefunction be factorised into?
Wavefunction (x,y,z) = Wavefunction (r, θ, φ ) = R(r) x Y(θ, φ )
R(r) = radial wavefunction and shows how the wavefunction varies as r changes (distance from nucleus)
Y(θ, φ ) = angular wavefunction and shows the overall orbital shape.
What happens when the wavefunction = 0?
It is a node.
What are the two types of nodes?
Radial Node = when R(r) = 0
Angular Node = when Y(θ, φ ) = 0
What does R(r) contain information on?
How the wavefunction behaves as a function of distance (r) from the nucleus
When are there no radial nodes?
The first time an orbital appears.
How do you work out the number of nodes?
n-(l+1)
What happens to s-orbitals?
Only s-orbitals start with R(r) > 0
What is R(r)squared?
The electron density at a specific point in space, as a function of distance (r) from the nucleus only.
What is the problem with R(r)squared?
It doesn’t take into account the amount of space available for the electron, and can be misleading.
What is the radial distribution function?
It describes the probability of finding an electron in a spherical shell of thickness, as a distance (r) from around the nucleus.
What does the maximum in the rdf tell us?
The most probable distance from the nucleus of finding an electron.
What happens to the R(r) value at the nucleus?
S-orbitals have +ve R(r) values at the nucleus, all other orbital types have an R(r) value of 0 at the nucleus.
What is penetration with orbitals?
The s orbital penetrates the p and d orbitals, so although r @ rdf max is on the s orbital pattern, and furthest away from nucleus, the penetration can mean that an electron in s orbital can get closer to the nucleus.
What happens to the angular wavefunction?
s-orbitals have a fixed angular wavefunction, so s-orbitals are spherical.
p, d and f orbitals angular wavefunctions do vary so they aren’t spherical.
