INORGANIC CHEMISTRY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site actinide Actinides element Z outermost electrons valences actinium (Ac) 89 6d17s2 3 thorium (Th) 90 6d27s2 4 protactinium (Pa) 91 5f26d17s2 4, 5 uranium (U) 92 5f36d17s2 3, 4, 5, 6 neptunium (Np) 93 5f46d17s2 3, 4, 5, 6, 7 plutonium (Pu) 94 5f67s2 3, 4, 5, 6, 7 americium (Am) 95 5f77s2 3, 4, 5, 6 curium (Cm) 96 5f76d17s2 3, 4 berkelium (Bk) 97 5f97s2 3, 4 californium (Cf) 98 5f107s2 2, 3 einsteinium (Es) 99 5f117s2 2, 3 fermium (Es) 100 5f127s2 2, 3 mendelevium (Md) 101 5f137s2 2, 3 nobelium (No) 102 5f147s2 2, 3 lawrencium (Lr) 103 5f146d17s2 3 Any member of the series of elements with atomic numbers from 89 (actinium) to 103 (lawrencium). The actinides are, in order of increasing atomic number: actinium, thorium, protactinium, uranium, neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium, and lawrencium. Each actinide is analogous to the corresponding member of the lanthanide series. They are separated by ion-exchange chromatography. The elements through uranium occur in nature; except actinium, they show valences higher than +3. The transuranic elements are synthetic; the +3 valence state becomes progressively more stable, and higher valences less stable. Related category    • INORGANIC CHEMISTRY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP