查看完整版本 : NH4+

sharpt 2012-11-29 10:07 PM

NH4+

鉀陽離子 即1+系佢要失去1個電子,點解NH4+ 系1陽離子  NH4唔系穩定?
唔系好明 NH3+HCI->NH4+ CI-

jmlo 2012-11-29 11:12 PM

回覆 1# 的帖子

NH4 byitself is not stable; it has an odd number of electrons. NH3 on the other hand is very stable. When a H+ is attached to it, NH4+ ion is formed.

In general, there is no absolute relationship between neutrality and stability.

sharpt 2012-11-30 12:22 AM

[quote]原帖由 [i]jmlo[/i] 於 2012-11-29 11:12 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=348577628&ptid=21193953][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
NH4 byitself is not stable; it has an odd number of electrons. NH3 on the other hand is very stable. When a H+ is attached to it, NH4+ ion is formed.

In general, there is no absolute relationship b ... [/quote]

都系唔系好明 點解NH3 NH4+ 我觀念系最外層電子2粒 8粒就唔系離子(唔駛失去or獲得電子) 系咪我配位共價用左電子轉移黎理解

jmlo 2012-11-30 02:02 AM

回覆 3# 的帖子

Having two or eight valence electrons does not mean necessarily a species is not an ion. For example, both neon and fluoride have eight valence electrons (1s2 2s2 2p6), but fluoride is an ion. Whether a species is an ion depends on the balance of the positive charges on nucleus and the negative charges of the electrons. If the species has more or less electrons that it should have (as dictated by the nuclear charges or the number of protons), it is an ion.

chungkin81 2012-12-1 12:10 AM

回覆 1# 的帖子

鉀原子的電子排佈是2, 8, 8, 1,只要鉀原子失去最外層的1粒電子,就會擁有8粒最外層電子。因為現在有19粒質子,18粒電子,所以形成帶+1電荷的鉀離子。

基於貴氣體不活潑的特性,擁有8粒最外層電子是穩定的 (除氦之外),這稱為八隅體結構。

至於在氨(NH3)的情況,氮原子的電子排佈是2,5,而氫原子的電子排佈是1,只要氮原子與3個氫原子各分享1粒電子,這樣氮就會有5粒 (本身來自氮)+1粒 x 3 (來自3個氫) = 8粒最外層電子,而每個氫就會1粒 (本身來自氫) + 1粒 (來自氮) = 2粒最外層電子。每個原子的電子排佈在這情況下穩定,因為氮的外層電子到達八隅體結構,而氫則電子層填滿。

但NH3的N有一對孤電子對,H+則沒有電子,NH3的孤電子對與H+結合,把孤電子對分享與H+,形成配位共價鍵(因為這個鍵是由其中一方捐出一對電子,而另一方則只接受這對電子)這樣H有2粒最外層電子,而N有8粒最外層電子。

sharpt 2012-12-4 04:49 PM

成個NH4系咪11質子 10電子 我唔知應唔應該咁問鉀有原子 NH4有冇中性?

[[i] 本帖最後由 sharpt 於 2012-12-4 05:15 PM 編輯 [/i]]

jmlo 2012-12-4 10:45 PM

回覆 6# 的帖子

[quote] 成個NH4系咪11質子 10電子 [/quote]
It is true for NH4+ ion.

[quote] 我唔知應唔應該咁問鉀有原子 NH4有冇中性? [/quote]
To make neutral NH4, one has to add one electron to NH4+ ion. NH4 neutral molecule does exist, but it is relatively unstable and easy to decompose.
頁: [1]
查看完整版本: NH4+