Name__________________________________
Differences Between Ionic and Covalent Compounds
A compound is defined as the chemical combination of two or more elements. A chemical bond is the
“glue” that holds atoms of different elements together. Bonds can be classified into two general types:
ionic and covalent. Ionic bonds generally occur between a metallic atom and a nonmetallic atom. The
ionic bond involves a transfer of electrons from the metallic atom to the nonmetallic atom, resulting in
a charge difference. The positively charged metal ion is then attracted to the negatively charged
nonmetal ion. Covalent bonding generally occurs between atoms that are nonmetallic and it involves
the sharing of electrons.
Properties such as melting point, solubility, and electrical conductivity are some of the properties that
can help you distinguish ionic from covalent compounds. In this experiment, you will observe several
properties of some ionic and covalent compounds and attempt to recognize some patterns among the
properties. The patterns are generalizations that do not apply to all ionic and covalent compounds.
Purpose:
To observe properties of various compounds and identify those properties as either primarily
ionic or primarily covalent.
Prelab:
1. Ionic compounds are generally made up of what kinds of elements?
2. Covalent compounds are generally made up of what kinds of elements?
3. Predict whether each of the following is primarily ionic or covalent.
a. sodium bromide (NaI) ________________ b. methane (CH4)______________________
c. calcium chloride (CaCl2)___________________ d. ammonia (NH3)_____________________
Procedure:
1. Obtain samples of the seven compounds to be tested. Based on their formula,
determine the type of bond for each and record that information in the data table.
Also, record the phase at room temperature (solid, liquid, or gas).
2. Begin heating approximately 150 mL of distilled water in a beaker on a hot plate.
3. Place a small scoop of solid into a well of the spot plate. Add 2 squirts of hot water.
Stir with a stirring rod. If the solid dissolves, it is soluble. If some of it dissolves, it is
slightly soluble. If it does not dissolve, it is insoluble. Repeat with the other solids
using approximately the same amount of each solid Record the results in the data
table. DO NOT DISCARD THE LIQUID IN THE SPOT PLATE.
4.
Test the conductivity of each solution with a conductivity tester. Record your
results. Rinse out the spot plate.
5. For the solid substances, A,B,C,F, test the melting times of the compounds. Place a
SMALL amount of each on the foil lined metal lid. Place the lid on the ring stand and
begin heating it in the center. Rank them from fastest to slowest and record the
results.
