Transcript Exceptions to the Octet Rule Hybridization

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Objective
 Today I will be able to:
 Determine the exceptions to the octet rule
 Predict the molecular shape of a molecule using the VSEPR theory
 Apply hybridization to determining the orbital shape of a molecule
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Evaluation/ Assessment
 Informal assessment – Listening to group interactions as they
complete the exeptions to the octet Lewis Structure Practice
 Formal Assessment – Analyzing student responses to the exit
ticket and the Lewis Structure Practice.
Common Core Connection
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Make sense of problem and persevere in solving them
Reason abstractly and quantitatively
Use appropriate tools strategically
Look for and make use of structure
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Warm – Up
Explain: Hybridization Notes
Elaborate: Hybridization Practice
Evaluate: Exit Ticket
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What molecular shapes allow for a molecule
to have an expanded octet?
Draw the Lewis Structure for BF3
◦ What is its molecular shape?
◦ What angles are present in the shape?
◦ Polar or nonpolar?
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Today I will be able to:
◦ Predict the molecular shape of a molecule using the
VSEPR theory
◦ Predict the molecular shape of a molecule using the
VSEPR theory
◦ Apply hybridization to determining the orbital shape
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STEM Fair Presentations – January 22
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Warm – Up
Hybridization notes
Hybridization practice
Exit Ticket
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Atoms use their valence electrons to form
bonds.
How is it that they form bonds of equal
energy when some of the electrons come
from the s orbital and some come from the p
orbital??
Hybrid orbitals are orbitals of equal energy
(between the energy of s & p orbitals)
produced by the combination of two or more
orbitals on the same atom.
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An atom in a molecule may adopt a different
set of atomic orbitals (called hybrid orbitals)
than those it has in the free state.
See B&L pages 319-322 for explanation and
diagrams of electron promotion
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The hybridization of a particular molecule is
determined by the central atom.
We only need to worry about it’s valence
electrons.
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sp = 2 orbitals
Sp2 = 3 orbitals
sp3 = 4 orbitals
sp3d = 5 obitals
Sp3d2 = 6 orbitals
sp3d3 = 7 orbitals
BeF2
1) Focus on Be
2) Write the orbital diagram for Be
**You need to have 2 e- available to bond to F
3) Write a new orbital diagram
4) Promote electrons
Original
Hybrid
BCl3
1)
2)
3)
4)
Focus on B
Write the orbital diagram for B
Write a new orbital diagram
Promote electrons
http://www.dlt.ncssm.edu/tiger/diagrams/moleculargeometry/BCl3_Hybrid.gif
Carbon has 4 valence electrons
1s2 2s2 2p2
2 of the electrons are in the s orbital
and 2 are in the p orbital.
s & p have different shapes and
different amounts of energy.
To create 4 equal bonds, carbon’s one 2s and
three 2p orbitals fuse into 4 new identical
orbitals called sp3.
2p
Hybridization
sp3
2s
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What type of hybridization does BF3 have?
1s2 2s2 2p1
Empty
hybridized
orbitals are
dropped
2p
Hybridization
sp3
2s
sp2
So sp3
becomes
sp2
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Each lone pair of electrons has it’s own
hybridized orbital.
See next slide.
Oxygen e- configuration
1s2 2s2 2p4
(Use oxygen because it is the central atom)
2p
Hybridization
sp3
2s
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Draw the hybridization orbital diagram for
phosphorus in PCl3
http://www.mhhe.com/physsci/chemistry/esse
ntialchemistry/flash/hybrv18.swf
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Determine the shape of the following
molecules
◦ XeF4
◦ PCl5
◦ NH3