Across
- 5. chemical combination of two or more elements in a specific ratio
- 6. ability of a substance to conduct electricity or heat
- 9. group 2 elements in the periodic table;their reactivity is not as strong as that of alkali metals
- 11. group 1 elements in the periodic table,not including hydrogen;the most reactive of the metals
- 14. combination of symbols that represent a compound; the formula identifies the elements in the compound and the amount of each element
- 15. invisible negatively charged particle that orbits the nucleus of an atom
- 19. principle that matter is not created or destroyed in a chemical reaction; the mass of the products always equals the mass of the reactants
- 20. an experiment in which all reactants and all products of a chemical reaction are accounted for
- 21. substance that helps a chemical reaction to proceed more quickly
- 22. measure of atomic mass; 1 amu is equal to 1/12th the mass of a carbon 12 atom
- 23. pure substance that cannot be broken down into other substances; substance made up of only one type of atom
- 24. orbit of electrons around he nucleus of an atom
Down
- 1. cloudy mixture in which tiny particles of one substance are held within another and particles cannot be separated out from the other substance
- 2. catalyst involved in chemical reactions in living things
- 3. chemical reaction that absorbs energy
- 4. mass of one atom of an element calculated from the total number of protons,neutrons, and electrons of that atom; measured inatomic mass units (amu)
- 7. 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. chemical reaction that takes place in cells; food (sugar) reacts with oxygen to produce energy, water, and carbon dioxide
- 10. 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
- 11. a solution in which water is the solvent
- 12. number of protons in the nucleus of one atom of an element
- 13. change of state from a gas to a liquid
- 16. description of how a substance interacts with other substances, such as acids; chemical properties are observable only when a chemical change occurs
- 17. slow chemical change that occurs when oxygen in the air reacts with a metal
- 18. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy