actinium series
71Isotopes of radon — There are thirty four known isotopes of radon (Rn). The most stable isotope is 222Rn, which is a decay product (daughter product) of 226Ra, has a half life of 3.823 days and emits alpha particles. 220Rn is a natural decay product of thorium and… …
72Chemical element — The periodic table of the chemical elements A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus.[1] Familiar examples of …
73actinide — /ak teuh nuyd /, n. Chem. any element of the actinide series. [1940 45; ACTIN + IDE, on the model of LANTHANIDE] * * * Any of the series of 15 consecutive chemical elements in the periodic table from actinium to lawrencium (atomic numbers 89–103) …
74protactinium — /proh tak tin ee euhm/, n. Chem. a radioactive, metallic element. Symbol: Pa; at. no.: 91. Also, protoactinium. [1915 20; PROT + ACTINIUM] * * * ▪ chemical element (Pa), radioactive chemical element of the actinoid series of the periodic… …
75transition element — Chem. any element in any of the series of elements with atomic numbers 21 29, 39 47, 57 79, and 89 107, that in a given inner orbital has less than a full quota of electrons. Also called transition metal. [1920 25] * * * Any chemical element with …
76série — [ seri ] n. f. • 1715; lat. series, spécialisé dès le XVIIe en math. 1 ♦ Math. Somme d un nombre fini de termes. Série harmonique : somme des inverses des entiers. Série convergente, telle que la somme de ses n premiers termes tend vers une… …
77transuranium element — Any of the chemical elements after uranium in the periodic table (with atomic numbers greater than 92). All are radioactive (see radioactivity), with half lives ranging from tens of millions of years to fractions of a millisecond. Only two,… …
78History of the periodic table — The history of the periodic table reflects over a century of growth in the understanding of chemical properties, and culminates with the publication of the first actual periodic table by Dmitri Mendeleev in 1869.[1] While Mendeleev built upon… …
79Classification périodique — Tableau périodique des éléments Pour les articles homonymes, voir Tableau. Le tableau périodique des éléments, également appelé table de Mendeleïev, classification périodique des éléments (CPE) ou simplement tableau périodique, représente tous… …
80Classification périodique des éléments — Tableau périodique des éléments Pour les articles homonymes, voir Tableau. Le tableau périodique des éléments, également appelé table de Mendeleïev, classification périodique des éléments (CPE) ou simplement tableau périodique, représente tous… …
