You will learn how to write: electron configuration noble gas configuration orbital configuration Lewis Dot You will learn the principals of: Aufbau Hund’s Pauli Exclusion

Only electrons are involved with chemical reactions QUANTUM MECHANICS It’s all about electrons Only electrons are involved with chemical reactions Review electron: location charge symbol Quantum # tell you 4 things: l. Main energy level 2. shape of orbit 3. orientation 4. spin

ENERGY INCREASES AS ATOM GET BIGGER Principle Quantum #: energy level of electron indicates distance from nucleus ) 2 ) 8 ) 18 ) 32 ) 2N2 ENERGY INCREASES AS ATOM GET BIGGER

Principle Quantum #: energy level of electron indicates distance from nucleus ) 2 ) 8 ) 18 ) 32 )

Principle quantum number represented by 2n2 7 periods on PT 7 energy levels for e- Calculate #e- using 2n2 N represents energy level

Angular Momentum Quantum # Indicates shape of orbit s p d f S (can hold) 2e- P (can hold) 6e- D (can hold) 10e- F (can hold) 14e-

B O Al “ Electron Configuration” Now that you have learned principle quantum number and angular momentum quantum number you can now learn to write “ Electron Configuration” 2 ) 8 ) 18 ) 32 ) 1s2 ) 2s2 2p6 ) 3s2 3p6,3d10 ) 4s2 4p6 4d10 ) 5s2 5p6 5d10 B O Al

Aufbau Principle : Cobalt Krypton Silver an e- will occupy lowest level of energy available 4s2 will fill before 3d10 1s2 ) 2s2 2p6 ) 3s2 3p6, 4s2 3d10 4p6 5s2 4d10 5p6… Cobalt Krypton Silver

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d10 6f14 7s2 7p6 7d10 7f14

Noble Gas Notation Ne Ar Kr Xe Rn Did you notice how you had to write the first few electron configurations over and over? Uck!!! Simplify using Noble Gas Notation On periodic chart elements on far right are called … noble gases He Ne Ar Kr Xe Rn The have nice complete energy levels with no e- left over. They do not react with anything.

To simplify electron configuration we can use the noble gases. Na P Co K

Orbital Notation Magnetic Quantum # …orientation…x y z 1s2 , 2s2 2p6 px , py , pz 1s2, 2s2 2p6, 3s2 3p6 4s2, 3d10 dx2y2, dxy, dyz, dxz, dz2 Spin Quantum # … which way e- spins – ½ +½

Orbital notation shows magnetic & spin quantum # Hund’s principle: orbitals of equal energy are each occupied by one e- before any orbitals are occupied by a 2nd e-. Orbital notation shows magnetic & spin quantum # Boron Phosphorus Chromium

Can you identify these elements….backwards 5p3 4s1 4d8 2p2 5p4 5d1 4d11 3d8

3 rules governing electron configuration Aufbau Principle Hund’s Principle : Pauli’s Exclusion Principle: .

Aufbau Principle An electron occupies The lowest-energy level that can receive it.

Hund’s Principle: Orbital's of equal energy are occupied by one electron before any orbital is occupied by a second electron and all electrons in single occupied orbital's must have the same spin.

Pauli’s Exclusion Principle: No two electrons in the same atom can have the same set of four quantum numbers.

Block location tells what orbital being filled Block location tells what orbital being filled. s p d f Group location tells # of valence electrons

4s1 6s2 4p1 4p5 4s2 3d3 5s2 4d9

3 methods to represent electron locations 1. Electron configuration 2. Noble Gas configuration 3. Orbital Notation Fourth and final…. Lewis Dot configuration

Lewis Dot configuration Valence electrons: electrons in outer energy level. **** only outside electrons involved in Chemical Reactions**** B O Al K Cl There is a secret=== group # tells valence electrons

8. Sodium Carbon 9. Potassium Nitrogen Fluorine Phosphorus Silicone Bromine Beryllium Sulfur Chlorine Ws. 4.5 Lewis Dot Carbon Nitrogen Phosphorus Sulfur Aluminum Krypton Calcium

You will learn how to write: electron configuration noble gas configuration orbital configuration Lewis Dot You will learn the principals of: Aufbau Hund’s Pauli Exclusion