Question

Identify the correct pairs.

• A. Carbon dioxide - compound, gold - compound
• B. Gold - element, water - compound
• C. Iron - compound, carbon dioxide - element
• D. Iron - element, water - element

Answer 1

The correct option is B Gold - element, water - compound

An element consists of only one type of atoms. Gold $\left(\text{Au}\right)$ and iron $\left(\text{Fe}\right)$ are made of only one type of atoms i.e., gold and iron respectively. Hence, they are classified as elements.

Compounds are made of more than one kind of atoms, chemically combined in a definite ratio. Water $\left({\text{H}}_2\text{O}\right)$ is formed by chemical combination of hydrogen and oxygen in the ratio of 2:1 and carbon dioxide $\left({\text{CO}}_2\right)$ is formed by carbon and oxygen in the ratio of 1:2. Hence, water and carbon dioxide are classified as compounds.