Match each vocabulary term to its definition. 1. electrons two or more elements that have chemically combined 2. metals a horizontal row on the periodic table 3. period elements with properties intermediate between those of metals and nonmetals 4. compound a homogeneous mixture whose particles are too small to reflect or scatter light 5. solution positively charged, subatomic particles found in the nucleus of the atom 6. protons a vertical column on the periodic table 7. group elements that are malleable, polish to a luster, conduct heat and electricity well and tend to lose electrons in a chemical reaction 8. metalloids negatively charged, subatomic particles