pure substance that cannot be broken down into other substances by chemical or physical means.
substance containing two or more elements chemically combined in a fixed ratio.
smallest particle of an element
two or more atoms held together by covalent bonds
particles that make up atoms.
ubatomic particle with a single unit of positive electric charge (+)
ubatomic particle with a single unit of negative electric charge (-)
subatomic particle that has no charge (is electrically neutral)
one of several forms of an element, each containing the same number of protons in their atoms but a different number of neutrons (
atom that has become electrically charged as a result of gaining or losing an electron
a positively charged ion generated by losing an electron (s).
negatively charged ion generated by gaining an electron(s).
number of protons in an atom's nucleus; is unique for each element
the mass of an atom (usually number of protons plus number of neutrons)