CHEM 121-A Exam 2 Study Guide ACTUAL UPDATED QUESTIONS AND CORRECT
ANSWERS
empirical formula "inventory" of atoms present in the composition of a substance; just the ratios
, molecular formula atoms actually present in the unit of a substance
structural formula shows how atoms are put together into molecules or "other"
2 types of bonding 1. covalent - sharing of electrons; EX: nonmetals mostly; atoms share electrons to
get to noble gas configurations
2. ionic - not sharing, complete electron transfer; EX: salts and metals
coulomb's attraction and law force of attraction btwn positive or negative charges
I(force) = K(constant) X Q1(+ charge) X Q2(- charge)/R(distance of separation)
polyatomic ions cluster of atoms with a charge
nomenclature naming elements, compounds, etc.
starts with cation (+), then anion (-)
hydrated ionic compounds contain specific # of water molecules associated with each formula unit
naming molecular (covalent) bonds prefix / name of first element
prefix / name of 2nd element / "-ide" at the end
second element listed should have higher electronegativity
prefixes:
mono - 1 hexa - 6
di - 2 hepta - 7
tri - 3 octa - 8
tetra - 4 nona - 9
penta - 5 deca - 10
electronegativity tendency of an atom to attract a bonding pair of electrons; increases from left to
right & down to up
ANSWERS
empirical formula "inventory" of atoms present in the composition of a substance; just the ratios
, molecular formula atoms actually present in the unit of a substance
structural formula shows how atoms are put together into molecules or "other"
2 types of bonding 1. covalent - sharing of electrons; EX: nonmetals mostly; atoms share electrons to
get to noble gas configurations
2. ionic - not sharing, complete electron transfer; EX: salts and metals
coulomb's attraction and law force of attraction btwn positive or negative charges
I(force) = K(constant) X Q1(+ charge) X Q2(- charge)/R(distance of separation)
polyatomic ions cluster of atoms with a charge
nomenclature naming elements, compounds, etc.
starts with cation (+), then anion (-)
hydrated ionic compounds contain specific # of water molecules associated with each formula unit
naming molecular (covalent) bonds prefix / name of first element
prefix / name of 2nd element / "-ide" at the end
second element listed should have higher electronegativity
prefixes:
mono - 1 hexa - 6
di - 2 hepta - 7
tri - 3 octa - 8
tetra - 4 nona - 9
penta - 5 deca - 10
electronegativity tendency of an atom to attract a bonding pair of electrons; increases from left to
right & down to up
