Organic Chemistry MCAT Chapter 3: Bonding

bonds in which electrons are transferred from one atom to another

ionic

ionic bonds result in ___ held together by ___

ions; electrostatic interactions

bonds in which electrons are shared between atoms

covalent

the node of a p orbital is an area at the ___ where ___

nucleus; the probability of finding an electron is zero

when two atomic orbitals combine, a ___ is formed

molecular orbital

molecular orbitals are found mathematically by ___

adding the wave functions of the atomic orbitals

if the signs of the wave functions are the same, a ___ is produced

lower-energy (more stable) bonding orbital

if the signs of the wave functions are the opposite, a ___ is produced

higher-energy (less stable) antibonding orbital

sigma bonds are formed by ___ overlap

head on

pi bonds are formed by ___ overlap

lateral

all covalent bonds have ___

one sigma bond

double and triple covalent bonds have ___

pi bonds

the more bonds formed between two atoms, the ___ the overall bond length

shorter

___ bonds hold atoms more closely together and are stronger than ___ bonds, therefore requiring more energy to break

shorter; longer

individual pi bonds are ___ than sigma bonds

weaker

it is ___ to break only one of the bonds in a double bond, leaving a single bond intact

possible

___ in structures with resonance restricts ___, increasing ___

partial double-bond character; free rotation; rigidity

proteins exhibit limited rotation because of ___ in the ___ between ___

resonance; amide linkages; adjacent amino acids

___ is a way of making all the bonds to a central atom equivalent to each other

hybridization

___ is the percentage of an s-orbital mixed into a hybrid orbital

s character

s character of an sp³ orbital

25%

s character of an sp² orbital

33%

s character of an sp orbital

50%

a blend of a molecule’s resonance forms

resonance hybrid

the resonance hybrid is ___ stable than any individual resonance form

more

resonance delocalization of electrons occurs in molecules that have ___ bonds

conjugated

conjugation requires ___

alternating single and multiple bonds

conjugation aligns ___ down the backbone of the molecule

unhybridized p-orbitals

the various resonance forms of a molecule all contribute to the molecule’s ___

true electron density

___ resonance forms contribute more to a molecule’s true electron density

more stable

more stable resonance forms lack ___, form ___, or stabilize charges through ___

formal charges; full octets on more electronegative atoms; induction and aromaticity