Across
- 1. contains only one type of atom
- 3. the diagram to show how Covanlent bonds are made
- 6. a change in which energy leaves a system and enters the surrounding
- 8. a substance that increases the rate of a reaction but is not used up in the reaction
- 10. the name of the electrons in th outer most shell
Down
- 2. a change in which energy enters a system from the surroundings
- 4. formed wen two or more atoms bond together
- 5. the center of a atom
- 7. the mass number minus the atomic number equals this
- 9. everything is made up of these