Agenda. Warm Up. Objective. Electron Configurations. Where are the e- s in an atom? Quantum numbers can tell us. Principle Quantum Number (n) 10/14/14

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1 Warm Up Agenda Worksheet: Orbital shapes Review: Quantum numbers (PAP) (Quiz next class) Lots of handouts Whiteboards: Quantum numbers practice (PAP) Turn in Flame test Lab Coloring: periodic table s, p, d, f Orbital shapes worksheet (do it now) Notes: Electron configurations (quiz next class) Whiteboards: energy level diagrams practice Worksheet: energy level diagrams Whiteboards: orbital diagrams and electron configurations Homework: orbital diagrams and electron configurations New ConnectED assignment after today Objective express the arrangement of electrons in atoms through electron configurations Electron Configurations Where are the e- s in an atom? Quantum numbers can tell us Quiz over these next time e- address 4 of em Principle Quantum Number Angular Momentum Quantum Number Magnetic Quantum Number Spin Quantum Number Principle Quantum Number (n) Same as energy levels in Bohr model Tells you how far from nucleus electron is Can be integers from 1 to An energy level has n2 orbitals 1

2 Angular Momentum Quantum Number (l ) Tells you shape of orbital Atomic'Orbitals' electron is in Also called sublevel Integers from 0 to n- 1 Orbital shapes Shapes are: l = 0 ; s (sphere) l = 1 ; p (dumbbell) l = 2 ; d (clover) l = 3 ; f (goofiness) # of orbitals in each: s=1, p=3, d=5, f=7 ' Magnetic Quantum Number (ml ) Spin Quantum Number (ms) Tells you which orbital within a sublevel electron is in Orbitals can only hold up to 2 electrons Integers from l to +l l m +l Those 2 electrons must spin in opposite directions (pauli exclusion principle) Orbitals can only hold up to 2 electrons Options are +½ and ½ 2s 2px 2py 2pz Quantum Number Practice A quantum nut shell 1. Principal # 2. Ang. Mom. # 3. Magnetic # 4. Spin # energy level sublevel (s,p,d,f) orbital electron Go to other powerpoint 2

3 How do we document electrons? Energy Level Diagrams Every neutral atom has an equal number of protons and electrons (1 negative for every positive charge) Each box is an orbital So, for most atoms writing the quantum #s for every e- would take forever Orbitals can only hold up to 2 electrons Therefore, we created a shorthand way to do it It s called an electron configuration We use the letters to write sublevels instead of numbers Electron configurations (e configs.) tell us the position ( address ) of every electron in an atom In order to understand e configs, let s look at a model that can help us visualize where e- s hang out 3 Rules for filling orbitals Correlation b/w Ptable & Orbitals Pauli Exclusion Principle Aunau Principle Hund s Rule Pauli Exclusion Principle Aunau Principle No 2 electrons can have the same 4 quantum numbers So, any 2 electrons occupying the same orbital (having the same n, l, and ml) must have opposite spins building up We denote this using up and down arrows Electrons fill the lowest energy orbitals first 3

4 10/14/14 Aunau order Aunau order Hund s Rule every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin Energy Level Diagram practice Orbital Filling Sequence Orbital diagrams are flat energy level diagrams Use what you ve learned and the orbital filling sequence diagram to answer the questions on the orbital filling sequence worksheet 4

5 10/14/14 Electron configurations are orbital diagrams with numbers instead of arrows for electrons 1s 2 2s 2 2p 4 Electron configuration for oxygen Noble gas configurations Abbreviated electron configurations Noble gasses are the right- most column (family) Since electron configurations read like a book on the periodic table, we can just write the element at the end of the previous row (period) and continue from there [He] 2s 2 2p 4 Noble gas configuration for oxygen Correlation b/w Ptable & Orbitals Valence Electrons Octet rule Neutral Atoms vs. Ions 5