The state of matter is a physical property that describes the form a substance takes based on its temperature and pressure conditions. Iodine is mentioned as being 'solid,' which is one of the classical states of matter. The three main states include solid, liquid, and gas, with others such as plasma and Bose-Einstein condensates being less common.
Key characteristics of different states:
- Solid: Defined shape and volume, with particles closely packed together.
- Liquid: Defined volume but no fixed shape, allowing it to flow and take the shape of its container.
- Gas: Neither defined shape nor volume, with particles spread apart and moving freely.
Physical changes in state do not alter the chemical structure of a substance. For example, when iodine sublimes from solid to gas, it retains its chemical identity.