Bond Types

Purpose: Find the difference between covalent and ionic.

Safety Concerns:
Hot plates and hot glassware can cause burns.
Wear safety goggles and apron at all times.
Loose hair and clothing should be tied back.

Procedure:
1. Using a metal spatula place a small pea sized amount of the covalent compound on one side of an aluminum evaporating dish, and a small pea sized amount of the ionic compound on the other side of the same evaporating dish, observe the crystals with the naked eye and record all observations.
2. Try to crush each solid by gently pressing on each one with a glass-stirring rod. Make observations regarding the hardness of the crystals.
3. Place the aluminum-evaporating dish on the hot plate and heat the contents. Observe both solids to determine which one melts first. After one of the solids melt, discontinue heating. Allow the evaporating dish to cool on the counter top before disposing. Record the relative melting point (low or high) of the two compounds.
4. Obtain another small scoop of each compound and place into two separate beakers (ionic in one beaker, covalent in the other). Attempt to dissolve a small amount of the covalent compound in distilled water in a small beaker. Note whether the sample dissolves in water.
5. Test the dissolved samples for electrical conductivity using the conductivity tester (make sure the two electrodes are submerged in the solution, but only allow the electrodes to be submerged, not the rest of the conductivity tester). Record the conductivity results.
6. Test the solid sample (in the beakers in front of room where you got your samples to see if either of them conducts electricity.
7. Rinse all glassware with soapy water and the proper brushes.

Data Table:

Hardness
Melting
Dissolved
Conductivity
(Dissolved)
Conductivity
(Solid)
Appearance
Ionic Compound
Hard
2nd
Yes
Yes
No
Fine grained
White
Round
Covalent Compound
Soft
1st
No
No
No
Big
White

Analysis:

1. Valence electrons dictate how likely an atom is to bond with another atom and form a compound. If they are given or taken, the compound is ionic. If they