geçiş elementleri

التركية - الإنجليزية

تعريف geçiş elementleri في التركية الإنجليزية القاموس.

(Kimya) transition element

any of the group or metallic elements that have an incomplete inner (d) electron shell; they have multiple valencies and form coloured compounds and stable complex ions; the elements scandium to copper and those lying below them in the periodic table

Any of the metallic elements that have an incomplete inner electron shell and that serve as transitional links between the most and the least electropositive in a series of elements. They are characterized by multiple valences, colored compounds, and the ability to form stable complex ions. Also called transition metal. Any chemical element with valence electrons in two shells instead of only one. This structure gives them their outstanding ability to form ions containing more than one atom (complex ions, or coordination compounds), with a central atom or ion (often of a transition metal) surrounded by ligands in a regular arrangement. Theories on the bonding in these ions are still being refined. The elements in the periodic table from scandium to copper (atomic numbers 21-29), yttrium to silver (39-47), and lanthanum to gold (57-79, including the lanthanide series) are frequently designated the three main transition series. (Those in the actinide series and beyond, 89-111, also qualify.) All are metals, many of major economic or industrial importance (e.g., iron, gold, nickel, titanium). Most are dense, hard, and brittle, conduct heat and electricity well, have high melting points, and form alloys with each other and other metals. Their electronic structure lets them form compounds at various valences. Many of these compounds are coloured and paramagnetic (see paramagnetism) and (as do the metals themselves) often act as catalysts. See also rare earth metal

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