Chapter 1 Introduction and Review Organic Chemistry, 6th Edition L. G. Wade, Jr. Chapter 1 * Definitions Old: ?derived from living organisms? New: ?chemistry of carbon compounds? From inorganic to organic, vitalism and W?hler, 1828 => Chapter 1 Chapter 1 * Atomic Structure Atoms: protons, neutrons, and electrons. The number of protons determines the identity of the element. Some atoms of the same element have a different number of neutrons. These are called isotopes. Example: 12C, 13C, and 14C => Chapter 1 Chapter 1 * Electronic Structure Electrons: outside the nucleus, in orbitals. Electrons have wave properties. Electron density is the probability of finding the electron in a particular part of an orbital.