Heisenberg’s Uncertainty Principle: (∆x)
(∆mv) ≥ h / 4π
-The more precisely the momentum is
unknown, the less precisely the
location/position is known.
-If we aren’t able to locate an electron
within the size of an electron (certain), then
you can’t find the momentum.
-You cannot find the position
because of the size of the electron.
Schrodinger developed Quantum
Mechanics, which incorporates both wave
and particle properties of matter.
1. N: energy level
2. Defines the shape of the orbital. (spdf)
3. 3D, number of orbitals per sublevel
(name orbitals in spdf)
4. spin
S Orbitals:
- 1 spherical orbital
- Centered around nucleus
- Radius increases with n
- As you move outwards (n goes up),
you get concentric areas of high
probability
-
Electron density: probability of where an
electron is likely to be at a given time.
Orbitals: wave functions, locations that the
electrons could be
-Solving the wave equation gives a set of
wave functions (orbitals) and corresponding
numbers
-Orbitals describe spatial distribution of
electron density
-orbitals are described by sets of quantum
numbers
This occurs with p, d, and f orbitals
as well
- Area of high probability is not
constant for that region, there are
concentric areas/nodes
P Orbitals
- Two lobes with a node between them
D Orbitals
Quantum Numbers:
-
Four have four lobes and take planar
form
Fifth one is donut shape
F Orbitals
- Complicated, 7 possible orbitals.
For one-electron hydrogen atom orbitals on
same level have same energy
Degenerate orbitals: orbitals of the same
energy (ex: 3 orbitals of the p sublevel)
For an atom that is filled with electrons, as
the number of electrons increases, so does
the repulsion between them. So for atoms
that are not Hydrogen, not all orbitals of the
same energy level are degenerate.
- Orbitals in the same sublevel are still
degenerate
- Energy levels start to overlap in
energy
More repulsion makes it less stable, so you
need more energy to make it stable again.
Electron Configuration:
- number in front is energy level
- Letter denotes type of orbital
-
Top number denotes number of
electrons in the orbitals
Spin: two electrons in the same orbital do
not have exactly the same energy
- The spin of an electron describes
magnetic field
Pauli Exclusion Principle: no two electrons
in the same atom can have exactly the same
energy, so no two electrons can have
identical sets of quantum numbers, and
every electron in an atom must differ by at
least one of the n, l, ml, and ms.
- Electron configuration does not
incorporate spin, as it does not
describe each individual electron
Orbital Diagrams:
- Each box represents one orbital
- Half arrows represent electrons, and
the spin of the electron.
Hund’s Rule: Same spin, one in each orbital
first. Then pair one at a time, opposite spin.
“for degenerate orbitals, the lowest energy
is attained when number of electrons with
the same spin is maximized”
- Separate is better than together
- When they do start pairing, pair with
opposite spin
-
Having electrons paired cancels out
the magnetic field
This allows us to see how many unpaired
electrons there are, because unpaired
electrons are slightly magnetic.
-
-
Irregularities occur when there are
enough electrons to half-fill s and d
orbitals on given row
If electrons aren't there and
repulsions aren't there, the level
won’t be high energy anymore