atomic structure - orbitals Flashcards
(21 cards)
atomic orbitals definition
probability regions of space that have particular shapes, where electrons are found
give the first 4 types of atomic orbital
s (sharp) = spherical
p (principle) = 2 lobes, 1 node
d (diffuse) = 4 lobes, 2 nodes
f (fundamental) = 6 lobes, 3 nodes
what are the 4 quantum numbers
n = principle QN - defines atomic shell/row of periodic table, can = any integer
l = angular QN, describes shape of orbital, can = any integer 1 -> n-1
ml = magnetic QN, described orientation of orbital relative to x, y, z, can = any whole no. from -l -> +l
ms = spin QN, can = +1/2 or -1/2
where do quantum numbers come from?
derived from schrodingers equations
what is the purpose of quantum numbers?
they describe/characterise an atomic orbital
what type of compounds are diamagnetic?
compounds with paired electrons
what type of compounds are paramagnetic?
compounds with unpaired electrons
how does orbital energy increase between shells?
n=1 < n=2 < n=3 < n=4 … going out further from nucleus energy increases
within shells how does orbital energy increase?
s < p < d < f … as angular QN l increases
what is the difference between a radial node and an angular node?
radial nodes - where radial function in wave function = 0 - sphere
angular nodes - where angular function in wave function = 0 - flat plane
what is the purpose of the Bohr-Bury rules
they describe the energy of orbitals
what are the 2 Bohr-Bury rules?
1- energy of an orbital is determined by n+l (principle QN + angular QN)
2- when 2 orbitals have the same n+l values, orbital of lower n value is lower in energy
- this dictates the order of filling
what are the 3 types of wavefunction graphs?
R(r) - standard wavefunction = atomic orbital, a single electron wavefunction
(R(r))^2 - wavefunction squared = probability density of finding an electron at a particular location
rdf- wavefunction x 4πr^2 - probability of finding electron within small radial space around nucleus
what does the maxima of an rdf graph represent?
the most probable distance from nucleus where the electron will be found
why is R(r)^2 always positive?
because its wavefunction squared, so much always be positive
why is rdf more useful that wavefunction^2?
wavefunction^” doesn’t account for volume
where can electrons not be found?
nodes - as wavefunction at nodes = 0
what is the area under the rdf curve represent?
probability of finding 1 electron - no matter which orbital so when drawing many orbital wavefunctions on the graph, they must seem to have similar areas under the curve
why does the maxima of the rdf curve shift to a larger r as QN n increases?
this is because the size of the orbital increases and it is at a higher energy level so its more likely that electrons are found further from the nucleus
how does stability change as QN n increases?
stability decreases as orbitals become further form nucleus, so at higher energy levels
this means on an rdf graph, consecutive orbitals with different n values would start/be drawn higher on the yaxis
is an electron more likely to be closer to the nucleus in a 2p or 2s orbital + why?
2s - looking at the rdf plots, although 2p is on average closer to nucleus judging by maxima, the 2s has a smaller peak at low r that penetrates the 2p, which gives it greater probability of being closer to the nucleus
