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单词 Poor metals
释义

Poor metals

原声例句
VOA Special 2020年3月合集

Hoover was born in the farm state of Iowa in eighteen seventy-four. His father was a poor metal worker who kept moving his family from state to state.

胡佛1874年出生在爱荷华州的农场,他的父亲是一位贫穷的金属工人,不断地带着家人从一个州搬到另一个州。

英语百科

Post-transition metal

Post-transition metals in the periodic table  Elements classified as post-transition metals by Masterton, Hurley and Neth:[1] Ga, In, Tl,  Sn, Pb, Bi, Po
  Also recognised by Huheey, Keiter and Keiter:[2] Al, Ge, Sb, Po; and by Cox:[3] Zn, Cd, Hg
  Also recognised by Deming:[4] Cu, Ag, Au (but he counted Al and groups 1 and 2 as 'light metals')[n 1]
  Elements that might be post-transition metals: At, Cn, Uut, Fl, Uup, Lv, Uus
Scatter plot of electronegativity values and melting points for metals (up to fermium, element 100) and some borderline elements (Ge, As, Sb, At). Elements categorised by some authors as post-transition metals are distinguished by their relatively high electronegativity values and relatively low melting points. High electronegativity corresponds to increasing nonmetallic character;[8] low melting temperature corresponds to weaker cohesive forces between atoms and reduced mechanical strength.[9] The geography of the plot broadly matches that of the periodic table. Starting from the bottom left, and proceeding clockwise, the alkali metals are followed by the heavier alkaline earth metals; the rare earths and actinides (Sc, Y and the lanthanides being here treated as rare earths); transition metals with intermediate electronegativity values and melting points; the refractory metals; the platinum group metals; and the coinage metals leading and forming a part of the post-transition metals.




The increased electropositivity of Be and Mg and the higher melting point of Be distances these light alkaline earth metals from their heavier congeners. This separation extends to other differences in physical and chemical behaviour between the light and heavier alkaline earth metals.[n 2]
CopperSilverGold
A crystal of a silvery metal crystal lying on a grey surface

In chemistry, post-transition metals are the metallic elements in the periodic table located between the transition metals (to their left) and the metalloids (to their right). Usually included in this category are gallium, indium and thallium; tin and lead; and bismuth. Which elements are counted as post-transition metals depends, in periodic table terms, on where the transition metals are taken to end and where the metalloids or non-metals are taken to start.

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更新时间:2025/6/19 0:14:09