Lesson 10
Home Up (1) Element or Compound (2) Metal, Nonmetal, or Inert Gas (3) Metallic or Covalent Bonding (4) Network or Molecular Materials (5) Element Formulas (6) Ionic or Covalent Compounds (7) Network or Molecular Compounds

 

(6) Ionic or Covalent Compounds

Obj. 6.  From the name of a compound, determine whether it is ionic or covalent.

There is more than one step to this process. From the name of the compound, you have to be able to figure out whether you have metal and nonmetal combined with one another, in which case you would have an ionic material, or whether you have only nonmetals, in which case you generally have covalent bonding. There are some exceptions to those generalities. The exceptions involve the polyatomic ion ammonium. Ammonium is a polyatomic cation and contains only nonmetals. So it is possible to have nonmetals that are found in ammonium, nitrogen and hydrogen, in the form of NH4 with a positive charge, combined with anions that are negatively charged and have an ionic compound and still have no metals atoms contained in it. You do have to be aware of that particular exception. In general, however, if you see that the compound contains metal with nonmetal, you have an ionic material and if it has only nonmetals, then you are dealing with a covalent material.

 

Exercises

Which of the following compounds are ionic and which are covalent?

a. water
b. ammonia
c. sodium oxide
d. potassium nitrate
e. sulfur(VI) oxide
f. manganese(IV) sulfide
g. carbon tetrachloride

 

Worked-Out Examples (a,b,c)

(a) Water contains hydrogen and oxygen, which are both nonmetals, therefore water is a covalent compound.

(b) Ammonia has the formula NH3. Because ammonia contains nitrogen and hydrogen, which are both nonmetals, it is a covalent material. It has covalent bonding.

Part (c) - sodium oxide contains a metal, sodium, and a nonmetal, oxygen and therefore it would be an ionic material. It would have ionic bonding.

 

Answers to Exercises

Which of the following compounds are ionic and which are covalent?

a. water - covalent
b. ammonia - covalent
c. sodium oxide - ionic
d. potassium nitrate - ionic
e. sulfur(VI) oxide - covalent
f. manganese(IV) sulfide - ionic
g. carbon tetrachloride - covalent

 

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E-mail instructor: Eden Francis

Clackamas Community College
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