Structure...

Newcastle Fans

Chem既structure你地點畫? any tips? (e.g. XeF2)
我成日都唔識畫  

Gray

搵多d書同past paper做參考,自己照畫

bobby_zamora

[QUOTE=Gray]搵多d書同past paper做參考,自己照畫[/QUOTE]
make use of 6n+2-v..
and do more..
u will find that....most of them are quite similar

nichart

i'll draw the bond within the molecule first,then to balance the no. of the outermost e of the central atom by adding lone pairs e
afterwards counting the total no. of e cloud and substitute to the suitable molecule shape

bobby_zamora

[QUOTE=bobby zamora]make use of 6n+2-v..
and do more..
u will find that....most of them are quite similar[/QUOTE]
多數troublesome o既都係有oxygen..for example./....Co3(2-)...so4(2-)

我就甘記e.g. Co3)

For carbon: there are 4e-(outermost)
for oxygen there are totally 6e-*3=18e-(same)

there are totally 4+18+2(2-)=24e-
and therefore 12 pair bond

and the main ptxygen should have 2 bonds...otherwise....it will carry a negative charge....and now for co3..there are 2 negative charge..therefore...there must be two oxygen with single bond..
and therefore...its shape...should be

bobby_zamora

[QUOTE=bobby zamora]多數troublesome o既都係有oxygen..for example./....Co3(2-)...so4(2-)

我就甘記e.g. Co3)

For carbon: there are 4e-(outermost)
for oxygen there are totally 6e-*3=18e-(same)

there are totally 4+18+2(2-)=24e-
and therefore 12 pair bond

and the main ptxygen should have 2 bonds...otherwise....it will carry a negative charge....and now for co3..there are 2 negative charge..therefore...there must be two oxygen with single bond..
and therefore...its shape...should be[/QUOTE]
you can count it..it does have totally 12 bond pair

Newcastle Fans

經過琴晚有個人教過我之後而家總算熟番D  
但我仲有兩個大問題...
1. 有部份resonance structure開頭諗唔到點畫 (e.g. SO3)
2. Dative bond[/COLOR]!!!!!!!!!!!!!!!!!!!!! 我唔知邊D要dative bond  

Newcastle Fans

[QUOTE=bobby zamora]make use of 6n+2-v..
and do more..
u will find that....most of them are quite similar[/QUOTE]
wt's "6n+2-v"

bobby_zamora

[QUOTE=Newcastle Fans]經過琴晚有個人教過我之後而家總算熟番D  
但我仲有兩個大問題...
1. 有部份resonance structure開頭諗唔到點畫 (e.g. SO3)
2. Dative bond[/COLOR]!!!!!!!!!!!!!!!!!!!!! 我唔知邊D要dative bond  [/QUOTE]
1.same as co3.....so3 is 2-...that means two single bond..you can see ha mine replies..
2.usually......dative bond appear in complex...

Newcastle Fans

[QUOTE=bobby zamora]2.usually......dative bond appear in complex...[/QUOTE]
咁乜野係complex

bobby_zamora

[QUOTE=Newcastle Fans]咁乜野係complex [/QUOTE]
....you will learn it in inorg chem

Newcastle Fans

[QUOTE=bobby zamora]....you will learn it in inorg chem[/QUOTE]
即係我可以唔理住  

bobby_zamora

[QUOTE=Newcastle Fans]即係我可以唔理住  [/QUOTE]
know the definition now

Newcastle Fans

[QUOTE=bobby zamora]know the definition now[/QUOTE]
而家見到有D睇完ans都唔知點解要dative bond

AirKID

bz好勁...
隔左咁耐d chem仲記得咁清楚

bobby_zamora

[QUOTE=Newcastle Fans]而家見到有D睇完ans都唔知點解要dative bond [/QUOTE]
usually..
.....when the central atom of a compound have more than 8 or less than 8 e-
...dative covalent bond occur..
e.g.NH3....Xecl4...

......for complex....due to the occurance of valence d-subshell orbital..
dative bond occur....

bobby_zamora

[QUOTE=Air KID]bz好勁...
隔左咁耐d chem仲記得咁清楚 [/QUOTE]
..................most of  them have forgotten la

beckham312oo

[QUOTE=bobby zamora]多數troublesome o既都係有oxygen..for example./....Co3(2-)...so4(2-)

我就甘記e.g. Co3)

For carbon: there are 4e-(outermost)
for oxygen there are totally 6e-*3=18e-(same)

there are totally 4+18+2(2-)=24e-
and therefore 12 pair bond

and the main ptxygen should have 2 bonds...otherwise....it will carry a negative charge....and now for co3..there are 2 negative charge..therefore...there must be two oxygen with single bond..
and therefore...its shape...should be[/QUOTE]呢招太慢了..i prefer 用transformation rule..

Newcastle Fans

[QUOTE=beckham312oo]呢招太慢了..i prefer 用transformation rule..[/QUOTE]
what is this