Across
- 4. that have a density of 5 or higher e.g., copper, zinc, lead, mercury, cadmium,nickel heavy metals are one type of substance monitored to determine water quality
- 7. change in the appearance or state of a substance that does not change the composition
- 12. atom that has become electrically charged because it has lost or gained electrons a positive ion is an atom that has lost one or more electrons a negative ion is an atom that has gained on
- 14. a material that electric charge can move through easily
- 16. neutral particle in the nucleus of an atom
- 18. description of how a substance interacts with other substances, such as acids;chemical properties are observable only when a chemical change occurs
- 19. 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
- 21. a table in which the elements are organized by their physical and chemical properties
- 22. combination of symbols that represent a compound; the formula identifies the elements in the compound and the amount of each element
- 24. an experiment in which one or more products of a chemical reaction can escape
- 25. substance that helps a chemical reaction to proceed more quickly
Down
- 1. positively charged center of an atom;contains protons and neutrons
- 2. 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
- 3. group 1 elements in the periodic table, not including hydrogen; the most reactive of the metals
- 5. group 2 elements in the periodic table; their reactivity is not as strong as that of the alkali metals
- 6. catalyst involved in chemical reactions in living things
- 8. a reaction that takes place when two or more substances react to form new substances
- 9. chemical combination of two or more elements in a specific ratio
- 10. invisible negatively charged particle that orbits the nucleus of an atom
- 11. substance that strongly resists the flow of electricity
- 13. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy
- 15. the sum of the number of protons and neutrons in an atom
- 17. property that describes the physical appearance and composition of a substance
- 20. new substance produced in a chemical reaction between reactants
- 23. element that has both metallic and non-metallic properties