Chemistry

2. a column of elements in the periodic table with similar properties
4. C3H8 is one of a group of molecular compounds called
6. has the general pattern AB+C->AC+B
8. the number of protons + the number of neutrons
11. produced when oxides react with water in the atmosphere
13. a characteristic behavior that occurs when the substance changes into something new, such as a reaction of an acid with a base
14. an ion that has a positive charge
16. a reaction in which two or more reactants combine to make a larger or more complex product
17. the elements that make up molecular compound

1. family with a valence of 7
3. a characteristic or description of a substance
5. a type of double displacement where acids and bases react together to produce a salt and water
7. a colourless sweet-smelling gas that dentists use to relax nerous patients
9. charged atoms
10. when an atom has a full outer shell
12. a base that can be added to lakes to neutralize the acid
13. a very rapid reaction of a substance with oxygen to produce compounds called oxides
15. a bond that forms from atoms sharing electrons
18. an ion that becomes negative by gaining an electron