Here's a breakdown:

* Liquids: The molecules in a liquid are close together but can move around each other. They have a fixed volume but not a fixed shape.

* Gases: The molecules in a gas are far apart and move freely in all directions. They have no fixed volume or shape.

Key Differences:

* Spacing: Molecules in liquids are closer together than in gases.

* Movement: Molecules in liquids move more freely than in solids but less freely than in gases.

* Shape: Liquids take the shape of their container, while gases fill the entire container they are in.

Example:

* Water (liquid): Water molecules are close together but can move around, allowing it to flow.

* Air (gas): Air molecules are far apart and move freely, making air compressible.

Important Note: While we often talk about liquids and gases being made up of molecules, there are some substances (like elemental metals like mercury) that exist as liquids at room temperature, even though their structure is not based on individual molecules.