Where is the Electron
Located?
The Quantum Model of the Atom

Heisenberg
uncertainty principle:
It is impossible to
determine both the
position and velocity
of an electron or any
other particle
What is the Address of the
Electron?


Principle Quantum Number (n): Indicates the
energy level occupied by an electron.
Angular Momentum (l): Indicates the shape of
the orbital (s,p,d,f,g)
Atomic Numbers and Quantum
Numbers


Magnetic Quantum Number (m): Indicates the
orientation of an orbital around the nucleus.
Spin Quantum Number (↓↑): Indicates which
way the electron is spinning
What are the Rules Governing
Electron Configuration?



Aufbau Principle: An electron occupies
the lowest energy orbital available
Pauli Exclusion Principle: Only two
electrons per orbital and they must spin
in opposite directions
Hund’s Rule: Each orbital of equal
energy must have one electron before a
second electron is added
Let’s Fill Up The Orbitals!
Summary of Orbitals
Principle
Sublevels
Quantum #
1
s
Number of Number of
Orbitals
Electrons
1
2
2
s, p
3
8
3
s, p, d
5
18
4
s, p, d, f
7
32
Predicting the 1s Orbital
Exceptions to Aufbau