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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
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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 • We base them on where the LAST e- is placed Where can we find electrons?
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 It’s like an address…
We have 1-7 Highest occupied ground state energy level = PT period # Main energy levels Bohr found Principle Energy levels
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 sublevels
Sublevels are distinguished by the shape of orbitals in them There are currently four of them s p d f Sublevel
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 Orbitals
1 orbital in this sublevel Sphere shape Total 2 e- possible Same shape in each level…just bigger Found in ALL energy levels S - 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 p - sublevel
5 orbitals in this sublevel Clover shape Total 10 possible e- Found in Energy Level 3 or higher. d - sublevel
7 orbitals in this sublevel Total 14 e- possible Complex shape Found in Energy Level 4 or higher f - sublevel
Energy - sublevel We will only commonly use s, p, d, and f!!
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 How we write where e- are
apartment story 5 32 e- 4 18 e- 3 f 8 e- 2 d 2 e- 1 p s nucleus
7p 6d 5f 7s 6p 5d 6s 4f 5p 4d 5s 4p 3d 4s 3p Increasing energy 3s 2p 2s 1s
7p 6d 5f 7s 6p 5d 6s 4f 5p 4d 5s 4p 3d 4s 3p 3s 2p 2s 1s s 1 2 = 1s
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. Electron Configuration Rules
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) Rules continued
Drawing Orbital Notation 1s 2p • 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: 2s
Lets try a few: • Orbital Notation for O • O = 8 e- • Orbital Notation for Cl • Cl = 17e- Orbital Notation 1s 2s 2p 1s 2p 2s 3s 3p
Electron Configuration # of electrons s 1 2 Principle Energy Level sublevel
Interpret the following Electron Configuration 4 electrons p 3 4 3rd Energy Level p sublevel
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 When doing a configuration…
K Cl Fe Pb Try a few
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 Answers
Write out the e- configuration for elements Hydrogen through and includingYttrium Tonight’s homework
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 Do Now:
Everything is the outside/highest PRINCPLE ENERGY LEVEL • Max is 8 e- total • 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3 Outerlevel (shell) Configuration
Ga Ra Mn Se Am Br Examples
Ga- 4s24p1 Ra- 7s2 Mn- 4s2 Se- 4s24p4 Am- 7s2 Br- 4s24p5 Examples
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 Sublevel (shell) configuration
F Ca Al Pa Mo Xe Examples
F- 2p5 Ca- 4s2 Al- 3p1 Pa- 5f3 Mo- 4d4 Xe- 5p6 Examples
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 Noble Gas configurations
Sr • W • Hg • Cl Examples – Noble Gas configurations
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 Charged atoms