Across
- 6. invisible negatively charged particle that orbits the nucleus of an atom
- 7. the smallest part of an element that is representative of that element;a neutral particle made up of a nucleus containing protons and neutrons, and in which the number of electrons equals the number of protons
- 9. an experiment in which all reactants and all products of a chemical reaction are accounted for
- 10. pure substance that cannot be broken down into other substances; substances made up of only one type of atom
- 11. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy
- 12. mass of one atom of an element calculated from the total number of protons, neutrons, and electrons of that atom;measured in atomic mass units
- 13. combination of symbols that represent a compound; the formula identifies the elements in the compound and the amount of each element
- 14. their reactivity is not as strong as that of the alkali metals
- 18. description of how a substance interacts with other substances, such as acids;chemical properties are observable only when a chemical change occurs
- 19. slow chemical change that occurs when oxygen in the air reacts with a metal
- 20. principle that matter is not created or destroyed in a chemical reaction; the mass of the products always equals the mass of the reactants
- 21. catalyst involved in a chemical reactions in living things
- 22. change of state from a liquid to a gas
- 23. chemical reaction that absorbs energy
- 25. change of state from a gas to a solid
- 26. a reaction that takes place when two or more substances react to form new substances
- 27. cloudy mixture in which tiny particles of one substance are held within another and particles cannot be separated out from the other substance
Down
- 1. change of state from a gas to a liquid
- 2. number of protons in the nucleus of one atom of an element
- 3. [in chemistry] vertical column of elements in a periodic table; elements in a family all have similar chemical properties; also called a group
- 4. the most reactive of the metals
- 5. change that results when two or more substances react to create a different substance or substances;the new substances have completely different properties from the original ones
- 8. amount of mass in a given volume of a substance
- 13. chemical reaction that takes place in cells; food[sugar] reacts with oxygen to produce energy,water, and carbon dioxide
- 15. a solution in which the water is the solvent
- 16. chemical combination of two or more elements in a specific ratio
- 17. group 17 elements in the periodic table; the most reactive non-metals
- 24. substance that helps a chemical reaction to proceed more quickly