Chemistry. a usually irreversible chemical reaction involving the rearrangement of the atoms of one or more substances and a change in their chemical properties or composition, resulting in the formation of at least one new substance: The formation of rust on iron is a chemical change.
How Are Newly Discovered Chemical Elements Named?Unlike common elements, newer elements are synthesized in a lab; they are not observed in nature. They are very unstable and quickly dissolve into other elements. So how do scientists name them?
Compare physical change.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019