Practice Worksheet Ionic Compounds: Formulas and Names

Name ______Period _____

Attached to these problems is a summary of how to name and write formulas of compounds. If you aren’t sure how to work a problem, consult the indicated topic.

1.Name the following ions.(See Topic B for more help).

Ion / Name / Ion / Name
K+ / O2-
Fe2+ / S2-
Ca2+ / H-
Co3+ / F-
Zn2+ / C4-
Mg2+ / N3-
Mn4+ / I-

2.Predict the formula of the ionic compound that would form between the ions given.

(The first one has been done for you). (See Topic A for more help).

Cation / Anion / Ionic Compound Formula
Ba2+ / O2- / BaO
Mg2+ / Cl-
Rb+ / S2-
Al3+ / Br
Na+ / C4-
Ca2+ / N3-
Sr2+ / NO3-
NH4+ / Se2-
K+ / SO42-

3.Knowing the charge on the anion, deduce the charge on the cation in the following.

(See Topic C and D for more help).

Formula / Cation / Anion / Name
CuBr2 / Cu2+ / Br- / copper (II) bromide
Na2SO4 / Na+ / SO42- / sodium sulfate
Fe(OH)3
Ag3PO4
MnCO3
Cd(NO3)2
NiPO3
PbS
Al2(SO3)3
CoO
Fe(MnO4)2

4.a) Fill in the chart to indicate whether the combinations will describe an ionic compound or a covalent (molecular) compound.

metal + nonmetal
nonmetal + nonmetal
NH4+ + other nonmetals

b)Determine whether each of the compounds is molecular or ionic.

Then supply the missing formula or name.

(See Topics A & D for more help).

Name the following ionic compounds:

1)NH4Cl ______

2)Fe(NO3)3 ______

3)TiBr3 ______

4)Cu3P ______

5)SnSe2 ______

6)GaAs ______

7)Pb(SO4)2 ______

8)Be(HCO3)2 ______

9)Mn2(SO3)3 ______

10)Al(CN)3 ______

Write the formulas for the following compounds:

11)chromium (VI) phosphate ______

12)vanadium (IV) carbonate ______

13)tin (II) nitrite ______

14)cobalt (III) oxide ______

15)titanium (II) acetate ______

16)vanadium (V) sulfide ______

17)chromium (III) hydroxide ______

18)lithium iodide______

19)lead (II) nitride ______

20silver bromide ______

A.Predicting Ionic Compound Formulas

  • An ionic compound is neutral overall: (+) charge of cations + (-) charge of anions = 0
  • If the charges of the cation and anion don’t add up to be zero, then sum to zero or

“criss-cross” the charges (make sure you reduce the charges to lowest terms before you criss-cross” them).

ex. Ba2+ O2- → sum to zero → BaO

Fe3+O2- → “criss-cross” → Fe2O3

  • The cation is written first.
  • When using a subscript for a polyatomic ion, put the entire polyatomic ion in ( ).

B.Naming Ions

Cation: Use element name “as is” or use ex. Li+ is the “lithium” ion

a Roman Numeral to specify chargeex. Mn2+ is “manganese(II)”

Anion:Replace end with “ide”ex. C4- is carbide (carbon + ide)

C.Predicting Charge of cation from a Formula

Cations other than group I, group II, silver, cadmium, zinc and aluminum can have variable charge. Since an ionic compound is neutral overall, the charge on the metal cation can be determined based on the anion charge:

Total charge of cations + Total charge of anions = 0

Ex. PbO: The charge on O is –2, so the charge on Pb must be +2.

FeBr3: The total anion charge is 3x(-1) = -3, so the charge on Fe must be +3.

(“Reverse” criss-cross!)

D.Naming Chemical Compounds

  1. Ionic Compounds

a) Name the metal or the polyatomic ion “ammonium”.

b) Then the anion, ending in “ide” (or polyatomic ion name)

CaCl2 / calcium chloride
CaCO3 / calcium carbonate
FeO / iron(II) oxide
(NH4)2CO3 / ammonium carbonate