Download Electron Configurations

Electron
Configurations
Objective: express the
arrangement of electrons in atoms
through electron configurations
and Lewis valance electron dot
structures.
Electron Locations
• According to the Heisenberg Uncertainty
Principle we can not know the exact position and
motion of electrons with complete certainty.
• We can only describe the probable locations of
electrons.
• We will describe the location of electrons when
the atom is at its lowest energy .
• These are called “ground state” configurations.
• If electrons move to higher energy states this is
called “excited.”
Quantum Numbers
• There are four quantum numbers that
describe the location of all electrons in an
atom.
• No two electrons in the same atom can
have the same set of four quantum
numbers that describe their location.
• This is called the Pauli Exclusion Principle.
Quantum Numbers
• Erwin
Schrodinger
produced
mathematical
equations to
describe the
wave like
behavior of the
electron.
Principle Quantum Number
called Energy Level
• Represented by letter “n”
• From 1 to 7 for present elements.
• Represents the average distance of the
electron from the nucleus.
• Also represents the amount of energy the
electron contains.
• 2n2 represents the maximum number of
electron per energy level.
Angular Momentum Quantum
Number
Called Sublevel
The secondary quantum number
“L” gives the shape of the
orbital.
L=1 is a “s” sublevel
L=2 is a “p” sublevel
L=3 is a “d” sublevel
L= 4 is a “f” sublevel
“s” sublevels are the simplest and
require the least amount of
energy for electrons to occupy.
s→p→d→f
Electrons will occupy which every
energy level and sublevel that
takes the least amount of
energy.
Sublevels
•
•
•
•
•
•
•
Energy Level
1
2
3
4
5
6
Possible Sublevels
s
s and p
s, p, and d
s, p, d, and f
s, p, d, f, and g (no g at present)
s, p, d, f, g, and h (no g or h)
Magnetic Quantum Number
Called Orbital
• mL has to do with the orientation of an orbital in
a magnetic field. Think of this as orientation
around the x-y-z axis in 3-dimensional space.
• Equal to ( –L to + L)
• Sublevel
Orbitals
Electrons
• s
1
2
• p
3
6
• d
5
10
• f
7
14
Spin Quantum Number
Called Spin
• The final quantum number is the spin
quantum number, it describes the spin
orientation of an electron.
• Two electrons can occupy the same
orbital, but they must have different spins.
• One positive and one negative.
Rules to arrange by.
• Heisenberg
uncertainty principle.
• Pauli exclusion
principle.
• Hunds Rule: The
most stable
arrangement is the
one with the
maximum number of
unpaired electrons.
• Aufbau: Electrons
are “lazy” and will go
to the lowest energy
level and sublevel
combination.
Electron Configurations
• Electron configuration, orbital notations,
and Lewis electron dot diagrams use the
quantum numbers to give the locations of
electrons in atoms.
• No two atoms will have the same electron
configuration.
• This is why all atoms have a different
bright line spectrum.