AP Biology Review of Chemistry

What four elements make up 96% of living matter?

carbon, hydrogen, nitrogen, oxygen

strongest bond

covalent

weakest bond

Van der Waals

difference between compound and molecule

compound: held together by any bond

molecule: held together only by covalent bonds

charge of anion

negative

charge of cation

positive

isotope

same # of protons

different # of neutrons

How many electrons in first 3 energy levels?

2 —> 8 —> 8

order of bonds from strongest to weakest

Covalent —> Ionic —> Hydrogen —> Van der Waals

covalent bond

sharing pair of electrons

-can be single, double, or triple

ionic bond

transfer of electrons

hydrogen bond

attraction of the negative oxygen from one bond to the positive hydrogen of another bond

polar covalent bond

big difference between electronegativities of the atoms and have unequal sharing of electrons

-produce polar molecules

nonpolar covalent bond

atoms have similar electronegativities so the electrons are shared equally

Which bond is too weak for receptor bonding?

Van der Waals interactions