🧪 States of Matter
Matter is anything that takes up space and has mass. It exists in three main states:
| State | Description | Examples |
|---|---|---|
| Solid | Fixed shape and volume; particles are tightly packed | Ice, rock, wood |
| Liquid | Fixed volume, but takes shape of the container | Water, milk, oil |
| Gas | No fixed shape or volume; particles move freely | Air, oxygen, carbon dioxide |
📌 Other states (less common but important):
-
Plasma – high-energy state with ionized particles (e.g., lightning, the sun)
-
Bose-Einstein Condensate – extremely cold state where atoms act as one
🔄 Changes in State (Phase Changes)
| Change Type | From → To | Example |
|---|---|---|
| Melting | Solid → Liquid | Ice melts into water |
| Freezing | Liquid → Solid | Water freezes into ice |
| Boiling/Evaporation | Liquid → Gas | Water boils into steam |
| Condensation | Gas → Liquid | Steam turns into water drops |
| Sublimation | Solid → Gas | Dry ice turns into carbon dioxide gas |
| Deposition | Gas → Solid | Frost forms from water vapor |
⚛️ Atomic Structure
An atom is the basic building block of all matter. It is very small and made up of three main parts:
| Particle | Charge | Location |
|---|---|---|
| Proton | Positive (+) | Inside the nucleus |
| Neutron | Neutral (0) | Inside the nucleus |
| Electron | Negative (–) | Orbiting around nucleus |
🧠 Important Facts:
-
The nucleus is the dense center of the atom (contains protons + neutrons)
-
Electrons move around the nucleus in energy levels (shells/orbitals)
-
A neutral atom has equal numbers of protons and electrons
🧪 Example: Hydrogen Atom
| Feature | Value |
|---|---|
| Protons | 1 |
| Electrons | 1 |
| Neutrons | Usually 0 |
| Atomic Number | 1 |
| Atomic Mass (approx.) | 1 |
🧠 Fun Facts
-
Atoms are the smallest unit of elements in the Periodic Table
-
Atoms combine to form molecules (like H₂O = 2 hydrogen + 1 oxygen)
-
A single human hair is about 1 million atoms thick
-
Each element has a unique atomic structure (especially proton count)
✅ Summary
-
Matter exists in 3 main states: solid, liquid, gas
-
Each state change depends on temperature and pressure
-
Atoms are made of protons, neutrons, and electrons
-
The structure of atoms explains how all materials behave and react