點解水銀mercury係液體? (最佳答案可得20分!)

Question

點解mercury係液體?
(從structure解釋... 唔好答我因為m.p.低過room tem. =.=)
點解佢係金屬但係都係液體? 仲有冇其他金屬都係咁, 可唔可以1齊解釋?

同埋, 點解mercury可以同noble gases form bond? 詳情係點樣?

如果可以的話, 可唔可以答埋... mercury既isotopes有咩特別?

最好用中文答, 但係keywords用英文... (e.g. bonding, ion呢d字眼)

唔該晒呀!!! =]

.... 救命 =.= 我係問[點解]水銀係液體, 唔係問水銀[係唔係]液體!!
同埋我想講, 水銀係Hg, 水係H2O, 水銀點會係水!? 唔好玩啦...
仲有, 水銀唔係唯1係液體金屬! caesium, francium, gallium係接近室溫底下都係液體!
我問得好認真架, 唔好為左駁果2分亂答問題啦!!

... 熔點同沸點都有得解釋 =.= 可以由structure同bonding解釋
例如如果係ionic/metallic structure通常m.p.&b.p.就比較高
simple molecular structure通常m.p.&b.p.就較低(week van der Waals force)
而且如果係polarised/saturated(即係只有single bond)/molecular mass大d, 熔點都會高d...
我依家就係問點解mercury係metallic structure但係又會有低熔點? 點解會有呢個例外?

第4個答案幾好, 但我之前都見過=.=
但我就係因為唔明所以想要中文..... thz ^^

Answer 1

這個問題的答案可參考以下網頁中的文章。文章要求讀者對電子亞層（subshell）和軌層（orbitals）有一定認識。

Mercury is puzzling in several ways. It's a liquid at room temperature and pressure, but all of its neighbors on the periodic table are solids. Mercury is much less reactive than cadmium or zinc. It's difficult to oxidize, and it doesn't conduct heat or electricity as well as other members of its group.

Why are most metals solids?
Most metals share their valence electrons with surrounding metal atoms. Picture the metal as a lattice of positive ions glued together by "sea" of shared valence electrons. This electron sea model explains many properties of metals. For example, metals conduct electricity because the shared electrons are free to move about; taking an electron from one part of the metal will cause electrons from surrounding areas to rush in and fill the hole. Metals can be drawn into wire or pounded into sheets because the metal ions can slide past each other but still be bound together by the shared valence electrons.
The electron sea model explains some trends in metal hardness and melting point. Harder, high-melting-point metals tend to share more valence electrons than softer, more easily melted metals. For example, magnesium has a higher melting point than sodium because Mg2+ centers are glued together by an electron sea with 2 electrons for every atom, while each atom in sodium metal contributes only one electron.

Mercury hangs on to its valence 6s electrons very tightly.
Mercury-mercury bonding is very weak because its valence electrons are not shared readily. (In fact mercury is the only metal that doesn't form diatomic molecules in the gas phase).
Heat easily overcomes the weak binding between mercury atoms, and mercury boils and melts at lower temperatures than any other metal. The thin valence electron sea makes mercury's ability to conduct electricity and heat much poorer than expected for a metal at that position in the periodic table.

Why is the pair of 6s electrons so inert?
The s electrons are able to come very close to the nucleus. They swing around very massive nuclei at speeds comparable to that of light. When objects move at such high speeds, relativistic effects occur. The s electrons behave as though they were more massive than electrons moving at slower speeds. The increased mass causes them to spend more time close to the nucleus. This relativistic contraction of the 6s orbital lowers its energy and makes its electrons much less likely to participate in chemistry- they're buried deep in the atomic core.

Why doesn't this effect make gold and thallium liquid too?
Let's compare the electronic configurations for gold, mercury, and thallium:
AtomAverage atomic massGround state configuration
Au196.9665[Kr] 4d10 4f14 5s2 5p6 5d10 6s1
Hg200.59[Kr] 4d10 4f14 5s2 5p6 5d10 6s2
Tl204.383[Kr] 4d10 4f14 5s2 5p6 5d10 6s2 6p1
All three atoms have very low energy 6s orbitals. But the gold 6s orbital is only half filled. Accepting an electron into that low energy orbital will lower energy overall, and metal-metal bonding is expected to be strong as a result. Still, the 6s electron is held tightly and gold's reputation as a 'noble metal' comes from its inertness.
Thallium is more massive, so the 6s pair is even more inert than in Hg. But thallium has a 6p electron. Remember that p electrons can't approach the nucleus as closely as s electrons; the p orbital has a nodal plane that passes through the nucleus. So that 6p electron is fairly reactive compared to the 6s electrons. That explains why the most common ion of thallium is Tl+, and not the +3 ion like B and Al and other members of its family.

Answer 2

將人地成篇文Copy & Paste唔係問題，但係Copy你都執番好D符號（'）呀！

Answer 3

唔緊要啦，編文的內容其實好簡單，基本上有中六程度的化學和足夠的英文都已經識睇。簡單的講一句：因為水銀最外層有兩粒電子，就好似貴族氣體最外面一層的兩粒電子一樣，可以自給自足，唔使同人share，所以atom同atom之間的交流少，使bonding弱囉。

Answer 4

以在下有限的見識, 現實中並無電子軌層, 同sub-shell.
所有金屬都係ionic/metallic structure,
可能係水銀的子量比較多, 所以水銀粒子互相排拆
減弱ionic/metallic structure的bonding,
但係超過80之後就會變成放射性金屬.(質子互相排拆)

Answer 5

我諗只可以從structure來講.....(不過真係無乜好解)
佢個金屬鍵既排佈為rhombohedral(三方晶系)http://en.wikipedia.org/wiki/Rhombohedral
我諗唯一解釋係........佢既metallic structure排佈唔夠好......令金屬鍵強度唔夠強
外界温度都能夠破壞一定量既金屬鍵......形成液體....
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其實呢d問題要解一定要好深入......結構個d要解得好仔細.......
我只能作膚淺既解釋......