End of chapter exercises

Give one word or term for each of the following descriptions.

1. A composition of two or more atoms that act as a unit.

2. Chemical formula that gives the relative number of atoms of each element that are in a molecule.

Give a definition for each of the following terms:

1. molecule

2. ionic compound

3. covalent network structure

4. empirical formula

5. ball-and-stick model

Ammonia, an ingredient in household cleaners, is made up of one part nitrogen (\(\text{N}\)) and three parts hydrogen (\(\text{H}\)). Answer the following questions:

1. is ammonia a covalent, ionic or metallic substance?

2. write down the molecular formula for ammonia

3. draw a ball-and-stick diagram

4. draw a space-filling diagram

In each of the following, say whether the chemical substance is made up of covalent, molecular structures, covalent network structures, ionic network structures or metallic structures:

1. ammonia gas (\(\text{NH}_{3}\))

2. zinc metal (\(\text{Zn}\))

3. graphite (\(\text{C}\))

4. nitric acid (\(\text{HNO}_{3}\))

5. potassium bromide (\(\text{KBr}\))

Refer to the diagram below and then answer the questions that follow:

1. Identify the molecule.

2. Write the molecular formula for the molecule.

3. Is the molecule a covalent, ionic or metallic substance? Explain.

Represent each of the following molecules using its chemical formula, structural formula and the ball-and-stick model.

1. nitrogen

2. carbon dioxide

3. methane

4. argon