Transcript Notes #3
Chemistry
Chapter 5
Notes #3
Rules
Neils Bohr
Added
on to Planck’s and Einstein’s theories
• Lowest available energy state of an atom
• Ground State
• When an atom gains energy =
• Excited State
This applies to the Atomic emission spectra!!
Rules
Heisenberg Uncertainty Principle
It is fundamentally impossible to know
precisely both the velocity and the
position of a particle at the same time
Ex. Blades of a running fan (on high)
That is how the electrons are traveling
Rules
Aufbau Principle
Electrons “fill”
atoms starting
at the lowest
energy and
moving out to
higher amounts
of energy
Excited vs.
Ground State
Rules
Pauli Exclusion Principle
A max of 2 electrons
will occupy a single
orbital
The electrons have
opposite spins
The opposite spin
requirement is born out
of quantum physics….2
electrons cannot have
the same quantum
number – therefore they
must have opposite
spins
Rules
Hund’s Rule
Single electrons with
the same spin occupy
each orbital (of a
multi-orbital sublevel)
before additional
electrons with
opposite spins
occupy the same
orbital.
Remember – Electrons are
all negative – so they repel
each other –meaning they
take as much space as
they can…
“Blocks on the table!
Noble gas Configuration
Shorthand to electron configuration
Steps:
Find the noble gas that comes directly
before the element you are looking at
Put the chemical symbol of the noble gas
in brackets
Then, continue the electron configuration
at the beginning of the row immediately
following the noble gas
Noble gas Configuration
Element
Atomic
#
Na
11
Ca
20
Sr
38
P
15
Br
35
I
53
e- conf
Noble gas Conf.