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Topic: Atomic Structure Aim: How are electron PELs further divided? Do Now: Construct a Lewis Dot diagram for Si . HW: castlelearning, rvw sheet. Remember when…. …we talked about PELs? What can you tell me about them? …you learned electron configurations? What can you tell me about them?
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Topic: Atomic StructureAim: How are electron PELs further divided?Do Now:Construct a Lewis Dot diagram for Si. HW:castlelearning, rvw sheet
Remember when… • …we talked about PELs? • What can you tell me about them? • …you learned electron configurations? • What can you tell me about them? • Let’s modify this model…
PELs can be divided • PEL # is only PART of the e- configuration of an element • PELs divided into sublevels • Sublevels are named with letters (s, p, d, or f) • The # of sublevels a PEL can have is equal to the # of the PEL • So… PEL 1 has 1 sublevel, PEL 2 has 2 sublevels, etc. • PELs higher than 4 would contain more than 4 sublevels – haven’t been named yet.
Sublevels within PELs • PEL 1, 1 sublevel, s • PEL 2, 2 sublevels, s and p • PEL 3, 3 sublevels, s, p, and d • PEL 4, 4 sublevels, s, p, d, and f
Shapes of Sublevels s is spherical p is pair of lobes along x, y, or z axis y d is double dumbbell and/or donut
Sublevels & Orbitals • Sublevels are divided into orbitals (increasing odd numbers, so s has 1, p has 3, d has 5, f has 7) • Each orbital can contain 2 electrons
Electron Configurations • Show how the electrons fill the orbitals in the PEL sublevels • 3 rules… • 1. Aufbau principle – e- enter orbitals w/the lowest energy first (so start w/the 1s) • 2. Pauli exclusion principle – max of 2 e- per orbital, each w/opposite spins ↑ or ↓ • 3. Hund’s rule – when e- occupy orbitals of equal energy, they don’t pair up until they have to
Hydrogen • Atomic #1, 1 electron • Goes in 1s • Electron configuration 1s1 • There is 1 electron in the 1st PEL, s sublevel 1 s 1↑ arrow indicates spin
Helium • Atomic #2, 2 electrons • Goes in 1s (it can hold 2 electrons, remember) • Electron configuration 1s2 • There are 2 electrons in the 1st PEL, s sublevel 1 s 2↑↓ arrows indicate spin
Lithium • Atomic #3, 3 electrons • Goes in 1s, then 2s • Electron configuration 1s2 2s1 • There are 2 electrons in the 1st PEL, s sublevel, 1 electron in the 2nd PEL, s sublevel • Total of superscripts must equal total # of electrons 1 s 2↑↓ 2 s 1↑ .
Beryllium • Atomic #4, 4 electrons • Goes in 1s, then 2s • Electron configuration 1s2 2s2 • There are 2 electrons in the 1st PEL, s sublevel, 2 electrons in the 2nd PEL, s sublevel 1 s 2↑↓ 2 s 2↑↓
Boron • Atomic #5, 5 electrons • Goes in 1s, then 2s, then 2p • Electron configuration 1s2 2s2 2p1 • There are 2 electrons in the 1st PEL, s sublevel, 2 electrons in the 2nd PEL, s sublevel, 1 electron in the 2nd PEL, p sublevel 1 s 2↑↓ 2 s 2↑↓ 2 p 1↑ ...
Carbon • Atomic #6, 6 electrons • Goes in 1s, then 2s, then 2p • Electron configuration 1s2 2s2 2p2 • There are 2 electrons in the 1st PEL, s sublevel, 2 electrons in the 2nd PEL, s sublevel, 2 electrons in the 2nd PEL, p sublevel • BUT – the two 2p electrons go into 2 different orbitals! They DON’T PAIR UP unless they have to! 1 s 2↑↓ 2 s 2↑↓ 2 p 2↑ .↑ ..
Nitrogen • What would this look like? • Electron configuration 1s2 2s2 2p3 1 s 2↑↓ 2 s 2↑↓ 2 p 3↑ .↑ .↑ .
Oxygen • What would this look like? • Electron configuration 1s2 2s2 2p4 1 s 2↑↓ 2 s 2↑↓ 2 p 4↑↓ .↑ .↑ .
Topic: Atomic Concepts • Aim: How do you write expanded electron configurations? • DN: • How many sublevels does the 3rd PEL have? • What are the sublevels of the 3rd PEL? • Write the FULL electron configuration for sodium. (use the s,p, etc) • HW: finish wkst on e- configs
Orbital Notation: Elements 1-10 • Pauli exclusion principle – max of 2 e- per orbital, each w/opposite spins ↑ or ↓ • Hund’s rule – when e- occupy orbitals of equal energy, they don’t pair up until they have to
Continuing… • Elements continue to fill PEL sublevels & orbitals in this fashion… • …until… • POTASSIUM. That jerk. • Look @ K’s electron configuration on Periodic Table • 2-8-8-1 • Why isn’t it 2-8-9? The 3rd PEL can hold more than 8 electrons (can hold up to 18)
Reason • Aufbau principle – e- enter orbitals w/the lowest energy first • Sometimes, low energy portions of higher PELs overlap into high energy portions of lower PELs • Huh? • I show you.
Potassium e- config: _______________________ basic e- config: _____________
Calcium e- config: _______________________ basic e- config: _____________
Scandium e- config: _______________________ basic e- config: _____________
Titanium e- config: _______________________ basic e- config: _____________
HOW DO YOU KNOW WHICH SUBLEVELS GET FILLED FIRST? • DIAGONAL RULE!!
We ♥ SHORTCUTS! • Start at the beginning of each arrow & follow it to the end • Ex: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p
Iodine e- config: _______________________ basic e- config: _____________
http://www.wwnorton.com/college/chemistry/gilbert/overview/ch3.htm#electron_configuration“electron configuration tutorial”