2.4 Other Structures of Matter

Describe the relationships between atoms, molecules and compounds. Be able to differentiate several different substances one from the other.

Study Guide

Explain each Concept

è A substance in which all the particles are alike is a pure substance.

è An element is a pure substance that cannot be broken down.

è Each element has a unique set of physical and chemical properties.

è Elements are classified as metals, nonmetals, and metalloids based on their properties.

è A compound is a pure substance made of two or more elements chemically combined.

è Each compound has a unique set of physical and chemical properties.

è The elements that form a compound always combine in a specific ratio by mass.

è Compounds are different from the properties of the elements that compose it.

è Compounds can be broken down into simpler substances by chemical changes.