Matter and Its Composition

Matter and Its Composition

Definition of Matter

• Matter is anything that has mass and takes up space
• It is the physical substance that makes up all objects, living and non-living

Composition of Matter

• Matter is composed of tiny particles called atoms
• Atoms are made up of three main parts:
  1. Protons: positively charged particles that reside in the nucleus (center) of the atom
  2. Neutrons: particles with no charge that reside in the nucleus along with protons
  3. Electrons: negatively charged particles that orbit around the nucleus

States of Matter

• Matter can exist in four main states:
  1. Solid: particles are closely packed and have a fixed shape and volume
  2. Liquid: particles are close together but are free to move past each other
  3. Gas: particles are widely spaced and are free to move in any direction
  4. Plasma: high-energy state of matter where atoms are ionized (lost or gained electrons)

Mixtures and Pure Substances

• A mixture is a combination of two or more substances, where each substance maintains its chemical properties
• A pure substance is a substance that consists of only one type of atom or molecule, with a fixed chemical composition

Physical and Chemical Properties

• Physical properties: characteristics of a substance that can be observed without changing its chemical composition (e.g. color, texture, melting point)
• Chemical properties: characteristics of a substance that involve a change in its chemical composition (e.g. reactivity with other substances)