Understanding Atomic Theory

Atomic Theory (Grade 8) Everything is made of atoms. Atoms are very tiny

particles that we cannot see with our eyes. Atoms are the basic building blocks

of all matter (solids liquids gases). Parts of an Atom Protons: positive charge (+) — in

the center (nucleus) Neutrons: no charge (0) — in the nucleus Electrons: negative charge (−) — move

around the nucleus Important Ideas Atoms of the same element are the same.

Atoms of different elements are different. Atoms join together to form molecules (example: H₂O).

In chemical reactions atoms are not created or destroyed, they just rearrange. Example

Water = 2 Hydrogen atoms + 1 Oxygen atom → H₂O