Bonding and Molecular Geometry Flashcards
Single covalent bond
One sigma (σ) bond
Double bonds
One sigma (σ) and one pi (π) bond
Triple bonds
One sigma (σ) and two pi (π) bonds
ranking covalent bond length and strength
Strongest to weakest: triple bonds, double bonds, single bonds
Shortest to longest: triple bonds, double bonds, single bonds
Number of sigma bonds in single bonds
1
Number of sigma bonds in double bonds
1
Number of sigma bonds in triple bonds
1
Number of pi bonds in single bonds
0
Number of pi bonds in double bonds
1
Number of pi bonds in triple bonds
2
Sigma-bonding orbitals in single bonds
Sp3
Sigma-bonding orbitals in double bonds
Sp2
Sigma-bonding orbitals in triple bonds
Sp
Number of sigma-bonding orbitals in single bonds
2
Number of sigma-bonding orbitals in double bonds
2
Number of sigma-bonding orbitals in triple bonds
2
Pi-bonding orbitals in double bonds
2p
Pi bonding orbitals in triple bonds
2p
Number of pi-bonding orbitals in double bonds
2
Number of pi-bonding orbitals in triple bonds
4
What is the greatest resonance contributor?
The most stable one:
* most stable resonance structure will have a full octet on every atom
* most stable resonance structure will have the smallest possible number of charges
* most stable resonance structure will have negative charges on the most electronegative atoms and positive charges on the least electronegative atoms
› C+ and H+ do not have full octets
› N+, O+, S+ do have full octets
When drawing the chair conformations, dashed lines point ________ and wedged lines point _______
Down
Up
The most stable chair conformation places the molecules highest priority substitute to in the __________ position
Equatorial
Eclipsed conformation
Represents the directly overlapping arrangement of atoms or functional groups when looking down the C-C bond. This conformation minimizes the distance between electron densities and thus, the molecule experiences more steric repulsion, leading to decreased stability
This conformation is the least stable when two largest groups are directly overlapping one another
Anti staggered conformation
Represented by the same functional group being 180° away from each other
This conformation is more stable than gauche since there is greater distance between the two groups
Gauche staggered conformation
Represented by the same functional groups being right next to each other
This conformation is less stable than anti since there is less distance between the two groups
Staggered conformation
Represents the non-overlapping arrangement of atoms or functional groups when looking down the C-C bond. This conformation maximizes the distance between electron densities and thus, the molecules experience less steric repulsion, leading to increased stability
The staggered conformation is the most stable when the two largest groups are directly opposite of one another
S orbital hybridization s-character and p-character
S-character: 100%
P-character: 0%
Sp orbital hybridization s-character and p-character
S-character: 50%
P-character: 50%
Sp2 orbital hybridization s-character and p-character
S-character: 33%
P-character: 66%
Sp3 orbital hybridization s-character and p-character
S-character: 25%
P-character: 75%
Resonance of N with lone pairs bonded to 3 things
It may seem like N with a lone pair bonded to 3 things is sp3, but due to being a part of the amide functional group, nitrogen experiences resonance and is actually sp2 hybridized
stereoisomers:
- molecules with the same molecular formula and connectivity but different spatial arrangement
- two classes: enantiomers and diasteriomers
enantiomers:
- non-superimposable, mirror images of each other
- opposite configuration at all chiral centers
