Atomic Theory

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Across
  1. 1. The first scientist to propose that all matter is made of atoms that combine in fixed ratios to form compounds.
  2. 7. A group of two or more atoms bonded together (like H₂O or CO₂).
  3. 8. A very small particle that orbits around the nucleus and has a negative (–) charge.
  4. 10. A pure substance made up of only one type of atom (like oxygen, gold, or hydrogen).
  5. 11. A tiny particle inside the atom’s nucleus that has a positive (+) charge.
Down
  1. 2. The scientist who discovered the electron and made the “plum pudding” model of the atom.
  2. 3. The center of an atom where protons and neutrons are found.
  3. 4. The scientist who discovered the nucleus by using the gold foil experiment.
  4. 5. A particle inside the nucleus that has no charge (it is neutral).
  5. 6. The scientist who showed that electrons orbit the nucleus in specific energy levels.
  6. 9. The smallest building block of matter; everything around us is made of atoms.