KEY
Naming & Formulas of Ionic & Covalent Compounds
Suzi Struggles Needs Some Help!!
Please correct each problem on Suzi’s paper and explain why she missed the problem.
There could be more than one mistake per problem.
Compound Name
or Formula
Suzi’s Answer
(this answer is WRONG)
Correct Answer
Explanation
Disilicon
hexabromide
Si.Br3
Si2Br6
Wrong subscripts for prefixes
Beryllium
phosphide
Be3(PO4)2
Be3P2
PO4 is phosphate not
phosphide
K2S
Dipotassium
monosulfide
potassium sulfide
LiOH
Lithium I Hydroxide
Lithium Hydroxide
MnO
Manganese. .oxide
Manganese II oxide
Al2O3
Aluminum2 Oxide3
Aluminum Oxide
No prefixes because this is
ionic
No roman numeral because
lithium is not a transition
metal
Mn is a transition metal and
needs a roman numeral 2
because its +2 charge
cancelled with O’s -2 charge
Subscripts are never used in
naming formulas
Sodium
permanganate
Na(MnO4)2
NaMnO4
Na has a charge of +1 not +2
CCl4
Carbon tetrachlorine
Carbon tetrachloride
All endings must end in -ide
Iron III sulfide
Fe(III)S
Fe2S3
SrF2
Strontium II difluoride
Strontium fluoride
KOH
Potassium oxygen
hydride
Potassium hydroxide
Fe(NO2)3
Iron. .nitrate
Iron III nitrite
BH6
Monoboron hexahydride
boron hexahydride
Ammonium
sulfide
NH2S
(NH4)2S
Mg3N2
Trimanganese dinitride
Magnesium nitride
Criss cross the charges of Iron
and Sulfur which are +3 and -2
Sr is not a transition metal so
does not need an roman # and
no prefixes because this is an
ionic compound
OH is a polyatomic ion named
Hydroxide not Oxygen and
Hydrogen
Iron is a transition metal so
needs a roman number 3 and
NO2 is nitrite not nitrate
Mono is only used if you have
one of the second atom
NH4 is ammonium and you
have to criss cross its +1
charge with S -2 charge
Mg is Magnesium not
Manganese and you do not
need prefixes since its Ionic
Barium
phosphate
Ba3(PO3)2
Ba3(PO4)2
Ti2CrO4
Titanium II chromate
Titanium I chromate
PO3 is Phosphite not
Phosphate
The subscript 2 is chromates
charge not Titanium’s. Since
there is no subscript outside of
chromate, then it is assumed
to be +1. You must add a
roman numeral 1 to represent
Titaniums charge.