Chemical Changes

compound a chemical combination of two or more elements.


chemical bond a link that atoms or elctrically charged particles can form with each other.


chemical formula  a way of using letters and numbers to show how much of each element is in a substance.


ion an elctrically charged particle with unuqual numbers of protons and electrons.


molecule  a group of bonded atoms that act as a single particle.


chemical property  a way of describing how a substance changes chemically with other subtances.

exothermic  a reaction that gives off energy.

endothermic  a reaction that absob heat