1. Solid

• Has a fixed shape and fixed volume

• Particles are tightly packed and vibrate in place

• Strong intermolecular forces

Examples

• Ice

• Wood

• Metal

2. Liquid

• Has a fixed volume but no fixed shape

• Takes the shape of its container

• Particles can move past each other

Examples

• Water

• Oil

• Milk

3. Gas

• Has no fixed shape and no fixed volume

• Expands to fill any container

• Particles move freely and rapidly

Examples

• Oxygen

• Steam

• Helium

4. Plasma

• An extremely energetic state of matter

• Made of ionized particles (charged particles)

• Found in stars and lightning

Examples

• The Sun

• Lightning

• Neon signs

Changes Between States

• Melting: Solid → Liquid

• Freezing: Liquid → Solid

• Evaporation/Boiling: Liquid → Gas

• Condensation: Gas → Liquid

• Sublimation: Solid → Gas

Example using water:

Ice → Water → Steam

What are the types of matter?

Matter can be classified in different ways. The main types of matter are:

1. Pure Substances

These are made of only one kind of particle.

a) Elements

• Made of only one type of atom

• Cannot be broken into simpler substances by chemical methods

Examples

• Gold

• Oxygen

• Iron

b) Compounds

• Made when two or more elements chemically combine

• Have fixed compositions

Examples

• Water (H₂O)

• Carbon dioxide (CO₂)

• Salt (NaCl)

2. Mixtures

These contain two or more substances physically mixed together.

a) Homogeneous Mixtures

• Uniform throughout

• Components are evenly mixed

Examples

• Salt water

• Air

• Vinegar

b) Heterogeneous Mixtures

• Not uniform

• Different parts can be seen

Examples

• Sand and water

• Salad

• Soil

Everything around us — air, water, rocks, plants, animals, and even your body — is made of matter.

An ionic compound is a compound formed when atoms transfer electrons from one atom to another.

This creates:

• positive ions (cations)

• negative ions (anions)

These opposite charges attract each other and stick together.

Example:

Sodium chloride (NaCl)

• Sodium (Na) loses 1 electron → becomes positive

• Chlorine (Cl) gains 1 electron → becomes negative

Then they attract and form salt.

Properties of Ionic Compounds

• Usually solid crystals

• High melting and boiling points

• Often dissolve in water

• Conduct electricity when melted or dissolved

Examples

Ionic CompoundFormulaSodium chlorideNaClMagnesium oxide Mg O Calcium chlorideCaCl₂

Uses of Ionic Compounds

1. In Food

Example: Salt (NaCl)

• Used for cooking

• Preserves food

• Adds taste

2. In Medicines

Some ionic compounds help the body.

Examples

• Calcium compounds for bones

• Iron compounds in supplements

3. In Agriculture

Farmers use ionic compounds in fertilizers to help plants grow.

Examples

• Potassium salts

• Nitrate compounds

4. In Batteries

Ions move inside batteries to produce electricity.

Used in

• phones

• laptops

• electric vehicles

5. In Cleaning Products

Some soaps and detergents contain ionic compounds that help remove dirt.

When Do We Use Ionic Compounds?

We use them:

• when cooking food

• when growing plants

• when making batteries

• in medicines

• in cleaning products

• in industries and laboratories

How the chemical atoms Bond Forms?

• Carbon has 4 outer electrons

• Hydrogen has 1 outer electron

• Both atoms share electrons so their outer shells become stable

CH4CH_4CH4​

This is methane, where one carbon atom shares electrons with four hydrogen atoms.

Example: Methane (CH₄)

• 1 carbon atom

• 4 hydrogen atoms

• 4 covalent bonds

  How do carbon atoms bond with hydrogen?

Carbon is special because it:

• can form 4 bonds

• bonds strongly with many elements

• forms long chains and rings

That is why carbon can make millions of organic compounds.