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yanrding

金虫 (正式写手)

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专业: 理论和计算化学

[求助] 金属性与非金属性有严格的定义吗？

网上找到的说法：

Metallic character is the name given to the set of chemical properties associated with elements that are metals. These chemicals properties result from how readily metals lose their electrons. Metallic character includes the ability to be reduced (e.g., participate in the thermite reaction), formation of ionic chlorides and basic oxides, and the ability to displace hydrogen from dilute acids.

Metallic Character and Periodic Table Trends
There are trends in metallic character as you move across and down the periodic table. Metallic character decreases as you move across a period in the periodic table from left to right. This occurs as atoms more readily accept electrons to fill a valence shell than lose them to remove the unfilled shell. Metallic character increases as you move down an element group in the periodic table. This is because electrons become easier to lose as the atomic radius increases, where there is less attraction between the nucleus and the valence electrons because of the increased distance between them.

1.金属性强弱的判断
(1)单质与水或非氧化性酸反映越剧烈，金属性越强。
(2)单质的还原性越强，离子的氧化性越强。
(3)最高价氧化物对应水化物碱性越强，金属性越强。
(4)单质与盐溶液的置换反应中，活动性强的金属置换活动性弱的金属。
2.非金属强弱的判断
(1)与氢气化合生成气态氢化物越容易，其气态氢化物越稳定，非金属性越强。
(2)单质的氧化性越强，阴离子的还原性越弱，非金属性越强。
(3)最高价氧化物对应水化物的酸性越强，非金属性越强。
(4)单质与盐溶液的置换反应，活动性强的非金属置换活动性弱的。
元素周期表从上倒下，从右到左金属性增强。从下到上，从左到右非金属性增强。

在量化层面上，对一个元素的金属性有定义吗？谢谢！

[ Last edited by yanrding on 2013-1-9 at 14:04 ]

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