Matter is the stuff that makes up everything around us. It includes all the things we can touch and see, and it takes up space. In chemistry, we group matter into three main states: solids, liquids, and gases.

1. Solids:

   • Solids have a fixed shape and volume.
   • Their tiny particles are packed tightly together in a set pattern.
   • Example: Ice, wood.

2. Liquids:

   • Liquids have a set volume but can change shape to fit their container.
   • Their particles are close together but can slide past each other.
   • Example: Water, oil.

3. Gases:

   • Gases don't have a fixed shape or volume.
   • Their particles are spread out and move around freely.
   • Example: Oxygen, carbon dioxide.

At a smaller level, matter is made up of atoms. Atoms are the tiniest pieces of elements. There are about 118 different elements, and each one has its own kind of atomic structure.

Interestingly, around 75% of everything in the universe is made from just hydrogen and helium.

Understanding matter and its different types is very important in chemistry. It helps us learn about chemical changes and reactions and how substances act in different states.