The easy way to keep tracks of electrons!
ELECTRON CONFIGURATION
DO NOW
Pick up your paperwork
 Pick up two handouts
 Get out Electron Configuration Notes, your
Blank Periodic Table, and your green periodic
table.

RULES
Aufbau Principle
 Each electron occupies the lowest energy orbital available.
Electrons are added from the ground state up. Electrons fill
in increasing energy order.
Pauli Exclusion Principle
 Each orbital can hold a maximum of only two electrons – one
spinning clockwise and one spinning counter clockwise.
Hund’s Rule
 The most stable arrangement of electrons in orbitals is to fill
singly and then go back and double up.
BLANK PERIODIC TABLE

Use this to help determine the different blocks:
s, p, d, f
BLANK PERIODIC TABLE
THE BLOCKS OF THE PERIODIC TABLE
ELECTRON CONFIGURATION

Includes the principle quantum number, the
sublevel and the number of electrons in the
sublevel.
ELECTRON CONFIGURATION
Hydrogen
Helium
H
He
1
2
1s1
1s2
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Li
Be
B
C
N
O
F
Ne
3
4
5
6
7
8
9
10
1s22s1
1s22s2
1s22s22p1
1s22s22p2
1s22s22p3
1s22s22p4
1s22s22p5
1s22s22p6
ELECTRON CONFIGURATION
Sodium
Magnesium
Aluminum
Silicon
Phosphorus
Sulfur
Chlorine
Argon
Na
Mg
Al
Si
P
S
Cl
Ar
11
12
13
14
15
16
17
18
1s22s22p63s1
1s22s22p63s2
1s22s22p63s23p1
1s22s22p63s23p2
1s22s22p63s23p3
1s22s22p63s23p4
1s22s22p63s23p5
1s22s22p63s23p6
Potassium
Calcium
K
Ca
19
20
1s22s22p63s23p64s1
1s22s22p63s23p64s2
ELECTRON HOTEL
First determine atomic number
 Then determine the electron configuration.

DO NOW
Pick up handout
 Bright Line Spectra lab due tomorrow
 2nd period paperwork revisions due tomorrow.
 5th period paperwork revisions due Friday.
 Get out Electron Configuration Notes, your
Blank Periodic Table, and your green periodic
table.

ELECTRON HOTEL
Carbon
Sodium
Phosphorus
Argon
Sulfur
Neon
Aluminum
C
Na
P
Ar
S
Ne
Al
6
11
15
18
16
10
13
1s22s22p2
1s22s22p63s1
1s22s22p63s23p3
1s22s22p63s23p6
1s22s22p63s23p4
1s22s22p6
1s22s22p63s23p1
ENERGY FILLING ORDER
ARROW DIAGRAM
1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d 6f
7s 7p 7d
DIAGONAL RULE
THE BLOCKS OF THE PERIODIC TABLE
TRY BISMUTH, #83
TRY BISMUTH, #83
2
2
6
2
6
2
10
6
1s 2s 2p 3s 3p 4s 3d 4p
2
10
6
2
14
10
3
5s 4d 5p 6s 4f 5d 6p
MERCURY, #80
2
2
6
2
6
2
10
6
1s 2s 2p 3s 3p 4s 3d 4p
2
10
6
2
14
10
5s 4d 5p 6s 4f 5d
ODDBALLS TO REMEMBER

You must memorize only:
 Chromium,
molybdenum, tungsten
 Copper, silver,

Lots of the “f” level elements

6d fills correctly; most f block elements do not
fill according to the rulesd.
THE BLOCKS OF THE PERIODIC TABLE
DO NOW

On a piece of paper see if you can do the
electron configurations for:
 Tantalum
(Z = 73)
 Curium (Z=96)
ANSWERS
Tantalum:
1s22s22p63s23p64s23d104p6
5s24d105p66s24f145d3
Curium:
1s22s22p63s23p64s23d104p6
5s24d105p66s24f145d106p67s25f8
DO NOW
Turn in Bright Line Spectra lab
 Turn in any revised paperwork
 Pick up both handouts
 Get out Electron Configuration notes

WHAT ARE IONS?
Charged particles
 ANION – atom that has gained electrons and is
more negative
 CATION – atom that has lost electrons and is
more positive.


So if the number of electrons has changed,
then the electron configuration has changed.
ELECTRON CONFIGURATION FOR IONS


First, write the regular electron configuration for the element.
If the ion is positive, take away electrons. If the ion is
negative, add electrons to the highest partially filled energy
level.
EXAMPLES:
Na
1s22s22p63s1
Na+1
1s22s22p6
Al
Al+3
1s22s22p63s23p1
1s22s22p6
F
F-1
H
H-1
1s1
1s2
1s22s22p5
1s22s22p6
ION ANSWERS
Magnesium
22s22p63s2
Mg
1s
12
+2 1s22s22p6
Mg
12
Lithium
22s1
Li
1s
3
+1 1s2
Li
3
Oxygen
22s22p4
O
1s
8
-2 1s22s22p6
O
8
Iron
22s22p63s23p64s23d6
Fe
1s
26
+3 1s22s22p63s23p64s03d5
Fe
26
EXCITED STATES
Atoms that have
absorbed energy and
are in an excited state
have electrons that have
moved to a shell level
that is higher than what
is normal. The electrons
that move come from
the valence electrons
(outermost electrons).
A REMINDER
ORBITAL DIAGRAMS
Another way to symbolize electrons in their
energy levels and sublevels.
 Has three basic symbols:

unoccupied
orbital
orbital with orbital with
one electron two electrons
RULES TO REMEMBER
Pauli Exclusion Principle
 Each orbital can hold a maximum of only two
electrons – one spinning clockwise and one
spinning counter clockwise.
Hund’s Rule
 The most stable arrangement of electrons in
orbitals is to fill singly and then go back and
double up.
ORBITAL DIAGRAMS
ORBITAL DIAGRAMS
TRY SOME
Do the orbital diagrams for:
SODIUM
SULFUR
ELECTRON CONFIGURATION SHORTHAND
Cannot be used until after the test on Atomic Theory.
Start with the noble gas the occurs before the
element in question. Then tack on the remaining
electron configuration.
Example:
Sodium 1s22s22p63s1
Shorthand: [Ne] 3s1
Copper 1s22s22p63s23p64s13d10
Shorthand: [Ar] 4s13d10
PRACTICE
Calcium 1s22s22p63s23p64s2
shorthand: [Ar]4s2
Oxygen 1s22s22p4
shorthand: [He]2s22p4
VALENCE ELECTRONS
These are the electrons in the outermost
energy level.
 Look for the highest principle quantum number
and count all the electrons in that level.

Sodium
Shorthand:
1s22s22p63s1
[Ne] 3s1
valence electrons: 1
VALENCE ELECTRONS
Copper
Shorthand:
Magnesium
Chlorine
1s22s22p63s23p64s13d10
[Ar] 4s13d10
valence electrons: 1
1s22s22p63s2
valence electrons: 2
1s22s22p63s23p5
valence electrons: 7
USING THE PERIODIC TABLE AS A SHORTCUT
ELECTRON DOT DIAGRAMS
The electrons in the outmost level are the ones
that are involved in bonding and the ones we
really care about (valence electrons).
 The symbol stands for the nucleus and all the
inner electron energy levels.
 Using the electron configuration for the atom,
choose the valence electrons.

ELECTRON DOT DIAGRAMS
EXAMPLES
Sodium 1s22s22p63s1
valence electrons: 1
Na
Copper 1s22s22p63s23p64s13d10
valence electrons: 1
Cu
Magnesium 1s22s22p63s2
valence electrons: 2
Mg
Chlorine 1s22s22p63s23p5
valence electrons: 7
Cl
HOMEWORK – START NOW
Do electron configuration and orbital diagrams
on the front
 Do electron configuration and electron dot
diagrams on the back side


Lab tomorrow – bring your logbook.