ATOMIC STRUCTURE
Electron Configuration
Building the Atom
ATOMIC STRUCTURE
Remember…
Atomic Number (Z) : the number of protons in
the nucleus of the atom.
Mass Number (A) : the number of protons and
neutrons in the nucleus of the atom.
Neutron Number (N) : A - Z = N
ATOMIC STRUCTURE
LOCATION OF ELECTRONS IN THE ATOM:
•Electron Cloud
•Energy Levels
•Sublevels
•Orbitals
ATOMIC STRUCTURE
LOCATION OF ELECTRONS IN THE ATOM:
•Sublevels have (degenerate states) that
we call orbitals.
These sublevels are named s, p, d, f, g, etc.
The energy level determines the number
of sublevels...
ATOMIC STRUCTURE
LOCATION OF ELECTRONS IN THE ATOM:
Sublevels:
s- one orbital
p- three orbitals
d- five orbitals
f- seven orbitals
Etc...
ATOMIC STRUCTURE
LOCATION OF ELECTRONS IN THE ATOM:
It turns out, in each orbital, there
can be a maximum of two electrons.
So...
s- 2 electrons total
p- 6 electrons total
d- 10 electrons total
f14 electrons total
ATOMIC STRUCTURE
Orbital diagrams and electron configurations
Orbital diagrams help show how the electrons
are distributed within the sublevels.
1s
NOTICE THAT WHEN
ELECTRONS PAIR
THEY HAVE OPPOSITE
SPINS.
ATOMIC STRUCTURE
PAULI EXCLUSION PRINCIPLE...
No two electrons can have the same
quantum numbers or no more than
two electrons can be found in any
given orbital.
ATOMIC STRUCTURE
HUND’S RULE:
the most stable arrangement of electrons
is that with the maximum number of unpaired
electrons, all with the same spin direction.
In other words…electrons don’t pair
until they have too!
ATOMIC STRUCTURE
Orbital Diagrams
What element is this????
1s
2s
2px
2py
2pz
3s
etc...
ATOMIC STRUCTURE
 Another
way to write this is by using
electron configuration notation
2
2
6
2
1s 2s 2p 3s
ATOMIC STRUCTURE
ORDER OF CHOICE:
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s,
4f, 5d, 6p, 7s, 5f, 6d, 7p...
Why? Energy of some orbitals
overlap higher orbitals.
Page 97
ATOMIC STRUCTURE
Let’s practice…
Assignment:
Electron Configuration Level One and Two
•Electron Configuration Wkst
ATOMIC STRUCTURE
Orbital diagrams and electron configurations
Orbital diagrams help show how the electrons
are distributed within the sublevels.
1s
NOTICE THAT WHEN
ELECTRONS PAIR
THEY HAVE OPPOSITE
SPINS.
ATOMIC STRUCTURE
Orbital Diagrams
What element is this????
1s
2s
2px
2py
2pz
3s
etc...
ATOMIC STRUCTURE
 Another
way to write this is by using
electron configuration notation
2
2
6
2
1s 2s 2p 3s
ATOMIC STRUCTURE
 Another
way to write this is by using
noble gas notation
2
[Ne]3s
Since Ne has a configuration of 1s22s22p6
ATOMIC STRUCTURE
Let’s practice…
Valence Electron Configuration
ATOMIC STRUCTURE
Connections:
Do you see any relationship between the
electron configuration and where the
element is located on the Periodic Table?
ATOMIC STRUCTURE
You should be able to…
•Write the electron configuration
•Draw the orbital diagram
•Write the noble gas notation
•And predict the element
ATOMIC STRUCTURE
Assignment:
•Electron Configuration Wkst 2