Atoms

1. a number of individuals assembled together or having some unifying relationship
3. measure of how easily an element will combine with other elements to form compounds
6. the basic unit of an element.
8. a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.
9. horizontal row of the periodic table
11. A substance that cannot be broken down into simpler substances by chemical means
12. (usually) poor conductors of heat and electricity, and are not malleable or ductile

2. a characteristic of a substance that can be observed or measured without changing the identity of the substance
4. the electrons in the outermost shell, or energy level, of an atom
5. elements on the periodic table that are malleable, lose electrons easily, good conductors of heat or electricity, and typically appear reflective
7. a tabular array of the chemical elements organized by atomic number
10. describes the ability of a substance to undergo a specific chemical change