Atoms, elements and compounds

• There are different types of atoms
• Atoms are the smallest particles that make up elements and compounds
• Every element has a Symbol
• The first letter of an element's symbol is always a capital letter
• The second letter of an element's symbol is always lowercase
• Element

  A pure substance made up of only one type of atom
• Compound

  Formed when atoms of different elements bond together
• Electrons

  Negative particles
• Protons

  Positive particles
• Nucleus

  Positive charged centre of atom
• Number of electrons in shells

  • 1-2
  • 2-8
  • 3-8
• Gold foil experiment

  1. Most particles passed through

  2. Some deflected

  3. Few greatly deflected
• Conclusion from gold foil experiment: Small dense positively charged nucleus, empty space
• describe what a atomic structure is:

  in a atomic structure there is neutral neutrons and positive protons in the positive nucleus. there is also negative electrons on the outer shell orbiting the nucleus which is surrounded by empty space.