Term |
Definition |
atom |
a small particle that is the building block of matter |
compound |
a substance made of two or more elements that are chemically joined in a specific combination |
element |
a substance made of only one kind of atom |
matter |
anything that has mass and takes up space |
mixture |
matter that can vary in composition |
molecule |
two or more atoms that are held together by chemical bonds and act as a unit |
substance |
matter with a composition that is always the same |
heterogeneous |
a mixture in which two or more substance are evenly mixed |
homogeneous |
a mixture in which two or more substance are evenly mixed, but not bonded together |
proton |
a positively charged particle in the nucleus of an atom |
nucleus |
the region at the center of an atom that contains most of the mas of the atom |
neutron |
an uncharged particle in the nucleus of an atom |
ion |
an atom that has a charge because it has gained or lost electrons |
atomic number |
the number of protons in the nucleus of an atom of an element |