1.3 Chemistry for Biology Flashcards
covalent bonds
sharing electrons
stronger
more permanent
needs more energy to break
non-covalent bonds
weaker but if there are a lot of them, they hold molecules together
less permanent
INTRAmolecular interactions
holds atoms together WITHIN a molecule
covalent bond/ionic
solid lines in a diagram
INTERmolecular interactions
forces BETWEEN molecules
non-covalent bonds
dashed lines in a diagram
interactions in DNA
outside is covalently linked together
bases have non-covalent hydrogen bonds
electronegativity
tendency of a covalently bonded atom to pull the electrons of the bond toward itself
ELECTRONEGATIVITY SCALE/ORDER
O > N»_space; S |C = H = P
high. | low
Non-polar: C-H, C-C
Polar: O-H, C-O, N-H
non polar covalent bonds
atoms with lower electronegativity levels
no dipole unless it is induced to form on when in proximity to another molecule
when 2 non polar atoms are close in proximity, they can induce a…
dipole/fluctuating dipole
ID-ID
when close to a non-polar group, Permanent dipoles can…
induce a dipole
Bond strength
covalent > Ions > Ion-PD > PD-PD > ID-ID
true strength of non-covalent bonds lies in their numbers and dynamism
polar covalent bond
Characterized by unequal sharing of electrons
- Results from electronegativity
Ability of atoms to attract electrons
hydrogen bonds
Between a hydrogen atom with slight positive charge and an electronegative atom of another molecule
Weaker than covalent bonds
- Special kind of dipole-dipole!
- Functional group with H is donor group
- Group supplying the lone pairs is the acceptor group
- Strength of hydrogen bond is influenced by the electronegativity of the atom involved in the bond
INDUCED DIPOLE BONDS
- Prescence of an ionic group/permanent dipole nearby can create a temporary induced dipole in an ordinarily nonpolar bond
