Term
| The __________ __________ __________ tells us that two pairs of electrons can go into the region of space between the carbon nuclei only if each pair has its own molecular orbital. |
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Definition
| 1) Pauli exclusion principle |
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Term
In ethylene, each carbon atom is bonded to __________ other atoms and there are no nonbonding electrons; three hybrid orbitals are needed, implying __________ hybridization.
This hybridization corresponds to bond angles of about __________ degrees. |
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Definition
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Term
| Each of the carbon-hydrogen __________ bonds in ethylene is formed by overlap of the __________ hybrid orbital on carbon with the __________ orbital of a hydrogen atom. |
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Definition
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Term
The C-H bond length in ethylene (1.08 angstroms) is slightly __________ than the C-H bond in ethane (1.09 angstroms) because the __________ orbital in ethylene has more __________ character (__________-__________ s) than an sp3 orbital (__________-__________ s).
The __________ orbital is closer to the nucleus than the __________ orbital, contributing to shorter bonds. |
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Definition
1) Shorter
2) sp2
3) S
4) One-third
5) One-fourth
6) s
7) p |
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Term
The C=C bond in ethylene (1.33 angstroms) is much __________ than the C-C bond (1.54 angstroms) in ethane, partly because the __________ bond of ethylene is formed from __________ orbitals (with more __________ character) and partly because there are __________ (number) bonds drawing the atoms together.
The second carbon-carbon bond is a __________ bond. |
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Definition
1) Shorter
2) Pi
3) sp2
4) s
5) Two
6) Pi |
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Term
For pi overlap to occur in ethylene, the second group of electrons must have parallel __________ orbitals which requires that the two carbon atoms be oriented with all their C-H bonds in a single __________.
Half of the __________ bonding orbital is above the C-C __________ bonds, and the other half is below.
The __________-bonding electrons give rise to regions of high __________ __________. |
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Definition
1) p
2) Plane
3) Pi
4) Sigma
5) Pi
6) Electron density |
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Term
The two ends of the __________ molecule cannot be twisted with respect to each other without disrupting the __________ bond.
Unlike __________bonds, a carbon-carbon __________ bond does not permit rotation.
This is the origin of __________-__________ isomerism: if two groups are on the same side of a double bond (__________) they cannot rotate to opposite sides (__________) without breaking the __________ bond. |
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Definition
1) Ethylene
2) Pi
3) Single
4) Double
5) Cis-trans
6) Cis
7) Trans
8) Pi |
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Term
Alkenes are said to be __________ because they are capable of adding hydrogen in the presence of a catalyst.
The product, an __________, is called __________ because it cannot react with any more hydrogen. |
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Definition
1) Unsaturated
2) Alkane
3) Saturated |
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Term
The presence of a __________ bond of an alkene (or an alkyne) or the __________ of a cyclic compound decreases the number of __________ atoms in a molecular formula.
These structural features are called __________ __________ __________; each element corresponds to __________ fewer hydrogen atoms than in the saturated formula. |
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Definition
1) Pi
2) Ring
3) Hydrogen
4) Elements of unsaturation
5) Two |
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