Topic 14. Chemical bonding and structure HL
14.1 Covalent bonding and electron domain and molecular geometries
Formal charge: the # of valence electrons – # of bonds – # of nonbonding electrons
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how far away from octet
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ex. H2O's formal charge is 6 - 2 - 4 = 0
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The rule of formal charge:
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when all atoms' FCs = 0, the molecule is more stable → preferred
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if both possible structures have a FC of 0 → most electronegative atom has the most negative FC
The structure on the right is preferred over the left.
From Pearson
From Pearson
14.2 Hybridization
The purpose of hybridization is to be able to form identical σ bonds of equal energy levels
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hybridized orbitals come from C, N, O, etc., never from H
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single bond = 1σ = sp³ hybridization
double bond = 1 σ + 1 π = sp² hybridization
triple bond = 1 σ + 2 π = sp hybridization
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* sigma bond (σ) and pi bond (π)
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to determine which type of hybridization has occurred, count the # of sigma bonds.
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