Across
- 3. the amount of heat energy required to raise the temperature of a unit mass of that substance by one degree Celsius
- 5. The horizontal rows of the periodic table
- 7. ions that are positively charged
- 11. Chemical reactions that release energy
- 12. an atom or molecule with a net electric charge due to the loss or gain of one or more electrons
- 15. the eight-electron arrangement in the outer electron shell of the noble-gas atoms
- 16. ions that are negatively charged
- 17. the exchange of "thermal” energy due to a temperature difference
- 18. the number of a chemical element in the periodic system, whereby the elements are arranged in order of increasing number of protons in the nucleus
- 20. the core electrons repelling the outer electrons, which lowers the effective charge of the nucleus on the outer electrons
- 21. a class of substances characterized by high electrical and thermal conductivity as well as by malleability, ductility, and high reflectivity of light
Down
- 1. a column in the periodic table of the chemical elements
- 2. Scientific notation is a way to express numbers as the product of two numbers
- 4. a class of reactions in which two molecules combine, usually in the presence of a catalyst, with elimination of water or some other simple molecule
- 6. a high-temperature redox chemical reaction between a fuel and an oxidant usually atmospheric oxygen that produces oxidize often gaseous products in a mixture termed as smoke
- 8. the lowest temperature that is theoretically can be
- 9. a group of rare gases that include helium, neon, argon, krypton, xenon, and sometimes radon and that exhibit great stability and extremely low reaction rates
- 10. a chemical element that forms a simple substance having properties intermediate between those of a typical metal and a typical nonmetal
- 13. A chemical element (such as boron, carbon or nitrogen) that lacks metal properties and is capable of forming anions, acid oxides, acids, and stable hydrogen compounds
- 14. chemical reactions in which the reactants absorb heat energy from the surroundings to form products
- 19. any of the six nonmetallic elements that constitute Group 17