Chemistry

12345678910
Across
  1. 1. Isotopes have a different number of..?
  2. 3. What type of energy is needed to start a reaction
  3. 7. What must occur between particles to react?
  4. 9. What type of test is used to identify metal ions?
  5. 10. Substances that only contain one thing are considered what?
Down
  1. 2. What is formed when halogens react with alkali metals?
  2. 4. How reactive are Group 1 metals
  3. 5. Ions with opposite charges form what type of bond?
  4. 6. Biological catalysts
  5. 8. Iron reactions with oxygen and what else to form rust?