Here are the most important things about gases to remember:
- Gases assume the shape and volume of their container.
- Gases have lower densities than their solid or liquid phases.
- Gases are more easily compressed than their solid or liquid phases.
- Gases will mix completely and evenly when confined to the same volume.
- All elements in Group VIII are gases. These gases are known as the noble gases.
- Elements that are gases at room temperature and normal pressure are all nonmetals.