From the list of words above, choose the one that corresponds to the definitions below.

1. Electrons present in the outer-most energy level of an atom.  For most atoms they are available to be gained, lost or shared.    _________________________

2. A term used to describe each of the fixed amounts of energy an electron in an atom may have.      _________________________

3. An atom or group of atoms that has a positive or negative charge because it has lost or gained electrons.    _________________________

4. An ion created from only one atom.      _________________________

5. A group of two or more "atoms" that function as a single ion.  _________________________

6. An ion with a positive charge.     _________________________

7. An ion with a negative charge.     _________________________

8. Description of a covalent bond that has an even distribution of charge due to an equal sharing of bonded electrons.   _________________________

9. Description of a covalent bond that has an uneven distribution of charge due to an unequal sharing of bonded electrons.   _________________________

10. A compound consisting of only two ions.   _________________________

11. A precise statement that tells which elements are in a compound and their respective ratios.      _________________________

12. A summary of a chemical change.  Written in terms of formulas, plus signs, and an arrow.  In the change, the substances to the left of the arrow are called reactants and interact to produce the substances to the right of the arrow called the products.    _________________________

13. A chemical bond formed by the attraction of oppositely charged ions.  _________________________

14. A chemical bond formed when atoms share pairs of electrons.  _________________________

15. The ability of a material to resist change. __________________________

16. The number written in front of a symbol or chemical formula to show the number of atoms or molecules.    _________________________

17. A number which is written to the upper right of a chemical symbol.  _________________________

18. A small lowered number written in a chemical formula that shows how many atoms of each element are present in a compound.  _________________________

19. A chemical reaction in which a single compound is broken down into two or more products;
general form is   AB   A + B  _________________________

20. A chemical reaction in which two or more reactants come together to form a single product;
general form is   A + B   AB  _________________________

21. A chemical reaction in which one element replaces another element in a compound;
general form is A + BX AX + B     _________________________

22. A chemical reaction in which two elements in different compounds exchange places;
general form is   AX  +  BY   AY + BX  _________ ________________

23. The number of electrons gained (-) or lost(+) by an atom.       _________________________

24. A neutral group of atoms held together by covalent or ionic bonds.  _________________________

25. A term that is represented in a chemical equation by an arrow symbol ( ) and is read as “produces or forms”.  _________________________

26. State's that the outer energy level needs to be filled with eight* electrons in order for an atom/ion to be stable. *Or two for the first five elements.      _________________________