electron configuration
DESCRIPTION
Electron configuration. The Quantum Mechanical Model. The e- is found inside a blurry “ electron cloud ” An area where there is a chance of finding an electron. Only found with 90% accuracy in the area. Each element has its own e- configuration for its ground state No charges - PowerPoint PPT PresentationTRANSCRIPT
ELECTRONCONFIGURATION
THE QUANTUM MECHANICAL MODEL
The e- is found inside a blurry “electron cloud”
An area where there is a chance of finding an electron.
Only found with 90% accuracy in the area
WHERE CAN WE FIND ELECTRONS? Each element has its own e- configuration for
its ground state No charges
We base them on where the LAST e- is placed
IT’S LIKE AN ADDRESS… State – city – street – house # State is called the Principle Energy level City is called the sublevel Street is called the orbital House # is the e- spin direction
PRINCIPLE ENERGY LEVELS
We have 1-7 Highest occupied ground state energy level =
PT period # Main energy levels Bohr found
SUBLEVELS Each energy level has increasing number of
sublevels Level 1 has 1 sublevel Level 2 has 2 sublevels Level 3 has 3 sublevels And so on….
Though 7 major levels…only 4 main sublevels are needed to describe existing atoms
SUBLEVEL Sublevels are distinguished by the shape of
orbitals in them There are currently four of them s p d f
ORBITALS In each sublevel there are specific orbitals An Orbital is a 3-D region in space an e- can
be found Does not have “hard and fast” boundaries
See next slide Each orbital can hold only 2 e- Mathematically found through wave function
WHAT’S GOING ON…
S - SUBLEVEL 1 orbital in this sublevel Sphere shape Total 2 e- possible Same shape in each
level…just bigger Found in ALL energy
levels
p - SUBLEVEL 3 orbitals in this sublevel Dumbbell shaped Total 6 e- Found in Energy Level 2 or Higher Node between each half of each orbital
Intermediate area between high probability areas
d - SUBLEVEL 5 orbitals in this sublevel Clover shape Total 10 possible e- Found in Energy Level 3 or higher.
f - SUBLEVEL 7 orbitals in this sublevel Total 14 e- possible Complex shape Found in Energy Level 4 or higher
ENERGY - SUBLEVELEnergy Level Sublevels1 s2 s, p3 s, p, d4 s, p, d, f5 s, p, d, f, g6 s, p, d, f, g, h7 s, p, d, f, g, h, i
We will only commonly use s, p, d, and f!!
HOW WE WRITE WHERE E- ARE State – city – street – house # State is called the principle E level City is called the sublevel Street is called the orbital House # is the e- spin direction
pd
f
1s
4
23
5
8 e-
2 e-
18 e-
32 e-
nucleus
Incr
easi
ng e
nerg
y
1s
2s
3s
4s
5s6s7s
2p
3p
4p5p6p
3d
4d5d
7p 6d
4f5f
1s
2s
3s
4s
5s6s7s
2p
3p
4p5p6p
3d
4d5d
7p 6d
4f5f
1s2=
1s
ELECTRON CONFIGURATION RULES
The way electrons are arranged in atoms. Aufbau principle- electrons enter the
lowest energy first. Must fully fill before move to next This causes difficulties because of the
overlap of orbitals of different energies.
RULES CONTINUED Pauli Exclusion Principle- no 2 e- can have
same set of 4 quantum # at most 2 electrons per orbital - different spins!!
Hund’s Rule- “up, up, up before down, down, down” All orbitals need to be filled w/one “up” spin
(positive--clockwise) before any in the sublevel is filled with a “down” spin (negative--counterclockwise)
DRAWING ORBITAL NOTATION
A box is used to represent each orbital. Arrows are used to represent each electron.
**remember opposite spins.
Example: the orbital notation for carbon is:
2s1s 2p
ORBITAL NOTATION Lets try a few: Orbital Notation for O
O = 8 e-
Orbital Notation for Cl Cl = 17e-
1s 2s 2p
1s 2s 2p 3s 3p
Electron Configuration
1s2# of electrons
PrincipleEnergy Level sublevel
3
Interpret the following Electron Configuration
p44 electrons
3rd Energy Levelp sublevel
WHEN DOING A CONFIGURATION… Use the total number of e- Slowly place e- in order till run out of e- Example
B 5e- First 2 in 1s2…3 left over Next 2 can go is 2s2 …1 left over Last one goes in 2p, but since only 1 left it is 2p1
Final configuration 1s2 2s2 2p1
TRY A FEW K Cl Fe Pb
ANSWERS K
1s2 2s2 2p6 3s2 3p6 4s1
Cl 1s2 2s2 2p6 3s2 3p5
Fe 1s2 2s2 2p6 3s2 3p6 4s2 3d6
Pb 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2
5d10 6p2
TONIGHT’S HOMEWORK Write out the e- configuration for
elements Hydrogen through and including Yttrium
DO NOW: Box all things written with the HIGHEST
PRINCIPLE energy level for each configuration of your homework Ex: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3
Circle the LAST THING WRITTEN for each configuration of your homework Ex: 1s2 2s2 2p6 3s2 3p6 4s2 3d6
OUTERLEVEL (SHELL) CONFIGURATION
Everything is the outside/highest PRINCPLE ENERGY LEVEL Max is 8 e- total 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3
EXAMPLES Ga Ra Mn Se Am Br
EXAMPLES Ga- 4s24p1
Ra- 7s2
Mn- 4s2
Se- 4s24p4
Am- 7s2
Br- 4s24p5
SUBLEVEL (SHELL) CONFIGURATION The last thing written for the e-
configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d6
Every element has its own ground level subshell configuration unique to itself
EXAMPLES F Ca Al Pa Mo Xe
EXAMPLES F- 2p5
Ca- 4s2
Al- 3p1
Pa- 5f3
Mo- 4d4
Xe- 5p6
NOBLE GAS CONFIGURATIONS In order to save time and your hand
when writing out electron configurations, one may use the Noble Gas Notation. A noble gas symbol is used in place of a
long list of electron configurations. Example: Ar: 1s2 2s2 2p6 3s2 3p6 = [Ar] Noble Gas Shorthand Configuration for Ca
Ca: [Ar] 4s2
EXAMPLES – NOBLE GAS CONFIGURATIONS
Sr W
Hg
Cl
CHARGED ATOMS Can do e- configurations for ions, but
must make sure to note that that is what you are doing! Same way, just use the number of e- in the
ion involved
