Predict the colour

有d cation 和 anion是有顏色的,例如MnO4^ -是紫色的,Cu^2+是blue/green,
去估顏色時,就要看看這些ion有冇顏色了,好似上美術堂這樣將cation和 anion顏色混合。

a. 由於Mg2+和NO3^ -都是無色的,所以magnesium nitrate 係colourless
b. Na+ colourless, permanganate purple,so sodium permanganate is purple
c. ammonium ion colourless, chromate ion green,so ammonium chromate is green
d. Iron(II)ion green, sulphate ion colourless,so Iron(II) sulphate is green.

2006-10-21 19:34:15 補充：
sorry,i have something wrongthe colour of chromate ion is yellow so the colour of ammonium chromate is yellow

2006-10-21 19:38:33 補充：
anions:Permanganate ion PurpleDichromate ion orangeChromate ion YellowCations:Chromium (III) ion greenManganese (II) ion Pale pink/colourlessCobalt (II) ion pinkNickel (II) ion greenIron (II) ion greenIron(III) ionyellowcopper(II) ion blue / greenI

A)Magnesium nitrate : coulourless+ colourless= colourless

B) Sodium Permanganate: colourless+purple= purple.

C) Ammounim Chromate: Colourless+ yellow= yellow

D) Iron (||) Sulphate: pale green+colourless =pale green

只有某d ions 係有水既情況係有色, 一定要有水! 應該係有個表俾你背ka, 除左個表外既, 只有好少係會有色, 所以你唔知佢有冇色既都係冇色ka la!

a Magnesium ion( colourless), nitrate ion(colourless) ~~~ The solution is colourless
b Sodium ion(colourless), permanganate ion(purple) ~~~ The solution is purple
c Ammonium ion(colourless), chromate ion(yellow) ~~~ The solution is yellow
d Iron(II) ion(green), sulphate ion(colourless) ~~~ The solution is green

俾埋d ion 既顏色你~
iron(II) ion, Fe 2+ -------- green
iron(III) ion, Fe 3+ -------- yellow
copper(II) ion, Cu 2+ --------- almost blue, but green in CuCl2 (copper(II) chloride) and Cu(NO3)2 ( copper(II) nitrate)
permanganate ion, MnO4 2- -------- purple
dichromate ion, Cr2O7 2- ----------- orange
chromate ion, CrO4 2- --------- yellow
chromium (III) ion, Cr 3+ ------- green
manganese (II) ion, Mn 2+ --------- pale pink, you also can say it is colourless
nickel (II) ion, Ni 2+ ------- green
cobalt (II) ion, Co 2+ ------ red with water, blue without water