| PROTONS | Components of atoms |
| ISOTONE | One of a group of atoms having the same number of neutrons but a different number of protons |
| RING | Closed chain of atoms; or, any one of the discs consisting of millions of moonlets orbiting Saturn (4) |
| COMPOUND | Any substance made up of identical molecules consisting of atoms of two or more chemical elements. |
| TAUTOMER | Either of two or more isomers of a chemical compound existing together in equilibrium and interconvertible by migration of atoms and bonds (8) |
| NUCLEARPHYSICS | A branch of science studying the structure of the central core of atoms (7,7) |
| ISOMERISM | Property of having the same formula but a different arrangement of atoms |
| AVUNCULAR | Benign source of atoms, very dim, emitting energy with introduction of uranium |
| CRYSTALS | Repeating three-dimensional arrangements of atoms, molecules or ions in the form of amethyst. beryl, garnet, opal, tourmaline (8) |
| CRYSTAL | An array of atoms in the form of a mineral such as quartz (7) |
| CHAIN | Bonded sequence of atoms forming a molecule; or, a series of connected events, house purchases, daisies, mountains or metal links (5) |
| VALENCE | Combining power of atoms, measured by the number of electrons gained, lost or shared when forming compounds (7) |
| METAMER | Compound that contains the same number and type of atoms as other compounds but with a different distribution of radicals |
| TRICYCLIC | Of a chemical compound, having three interconnected rings of atoms in its molecular structure (9) |
| STERIC | Of the spatial relationship of atoms in a molecule |
| ISOMER | Each of two or more compounds with the same formula but different arrangements of atoms (6) |
| MOLECULAR | Second cure-all made up of groups of atoms |
| FREERADICAL | An atom or group of atoms containing at least one unpaired electron and existing for a brief period of time before reacting to produce a stable molecule |
| NUCLEAR | Form of energy released from the core of atoms (7) |
| VALENCES | Combining powers of atoms |
