The Division of Adolescent Medicine provides primary and consultation services for adolescents and young adults between 12 and 21 years of age. We have a separate waiting room and examination area for these patients and offer services tailored to their needs and health care issues.
Modern atomic theory is generally said to begin with John Dalton, an English chemist and meteorologist who in 1808 published a book on the atmosphere and the behavior of gases that was entitled A New System of Chemical Philosophy.
atom definition. A unit of matter; the smallest unit of a chemical element. Each atom consists of a nucleus, which has a positive charge, and a set of electrons that move around the nucleus. (See Bohr atom.) Note: Atoms link together to form molecules.