Covalent and Noncovalent interactions

Different types of chemical interactions

covalent

ionic

hydrogen bonds

van der waals

hydrophobic effects

Of these interactions, which are noncovalent?

ionic

hydrogen bonds

van der waals

hydrophobic effects

Covalent bond

formed by atoms sharing their valence shell electrons to completely fill each atoms outermost shell

What makes a covalent bond even stronger

shorter and more bonds (can also depend of whats bonded)

Are covalent bonds polar or nonpolar? Give example(s)

Can be either depending on whether the atoms share the electrons equally or not

Polar: water

Nonpolar: methane

How to know if something is polar?

Electronegativity chart:

less than 0.5 nonpolar

more than 0.5 polar

Ionic interactions (charge-charge interactions or salt bridges

involves electrostatic attraction between oppositely charged ions

What is the electronegativity difference between atoms that participate in ionic interactions

greater than 2 (often between most and least electronegative atoms)

Hydrogen bonds

forms when a hydrogen that is covalently bonded to an electronegative atom is in proximity to another electronegative atom

KNOW HOW TO DRAW DONOR AND ACCEPTOR

What makes a hydrogen bond stronger?

donor and acceptor in linear alignment stronger

Van der waals interactions

occur between nonpolar molecules/atoms by temporary dipole moments because of fluctuation in the electron cloud

When does maximum van der waals attraction occur

at a distance slightly greater than the sum of the van der waals radii of the two atoms

Example of van der waals

stacking of bases in double stranded DNA

Hydrophobic effects

due to the tendency of nonpolar molecules to pack together close to get away from water

Hydrophobic effects is one of the main factors behind:

protein folding

protein-protein association

formation of lipid micelles

enzyme substrate complex formation

Types of interactions from strongest to weakest

covalent, ionic, h bond, hydrophobic effect, van de waals