lead element
31Élément-trace métallique — Pour les articles homonymes, voir ETM. La notion d’éléments traces métalliques, ou ETM tend à remplacer celle de métaux lourds qui a été et qui reste un concept mal défini car associant des métaux toxiques réellement lourds à d autres l étant… …
32lead — , led The past tense of the verb to lead is led. When lead is pronounced led it applies only to the metallic element …
33element — I (New American Roget s College Thesaurus) n. component, part, substance, constituent, ingredient; factor, principle, rudiment, fundamental. See cause, composition. II (Roget s IV) n. 1. [A part] Syn. component, constituent, factor, ingredient,… …
34Magnetic element — Element El e*ment, n. [F. [ e]l[ e]ment, L. elementum.] 1. One of the simplest or essential parts or principles of which anything consists, or upon which the constitution or fundamental powers of anything are based. [1913 Webster] 2. One of the… …
35Isotopes of lead — Lead (Pb) has four stable isotopes 204Pb, 206Pb, 207Pb, 208Pb and one common radiogenic isotope 202Pb with a half life of 53,000 years. The standard atomic mass is 207.2(1) u. It is the heaviest discovered element to have a stable isotope. (The… …
36nitrogen group element — ▪ chemical elements Introduction any of the chemical elements that constitute Group Va of the periodic table (see Figure >). The group consists of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). The elements share… …
37carbon group element — ▪ chemical elements Introduction any of the five chemical elements that make up Group 14 (IVa) of the periodic table namely, carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead ( …
38Chemical 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 …
39chemical element — Introduction also called element, any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed. This article considers the… …
40transuranium 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,… …
