1. Designed by Samuel Millar VERSION 1

2. NOTES Black text – CORE KNOWLEDGE – Red text – EXCEPTIONS TO THE PATTERNS Grey text – EXTENSION The colour and formula are given for the complex formed by each ion with each reagent, starting with the aqueous complex. In the case of NaOH and NH 3, the hydroxide precipitate produced is given, followed by the complex formed (if any) when excess (“xs”) of the reagent is added. The colours are named as CCEA wants them in the exam! The colour boxes hopefully give some indication of the actual shade. Most of the complexes involve six ligands and so are octahedral. However, chloride complexes take tetrahedral or square planar shapes.

3. Copper (II) and Cobalt (II) Cu 2+ blue soln [Cu(H 2 O) 6 ] 2+ blue ppt [Cu(OH) 2 (H 2 O) 4 ] insoluble in xs blue ppt [Cu(OH) 2 (H 2 O) 4 ] soluble – deep blue soln [Cu(NH 3 ) 4 (H 2 O) 2 ] 2+ yellow-green soln [CuCl 4 ] 2- Co 2+ pink soln [Co(H 2 O) 6 ] 2+ blue ppt [Co(OH) 2 (H 2 O) 4 ] insoluble in xs blue ppt [Co(OH) 2 (H 2 O) 4 ] soluble – yellow soln [Co(NH 3 ) 6 ] 2+ blue soln [CoCl 4 ] 2- ion aq NaOH NH 3 conc HCl

4. Iron (III) and Iron (II) Fe 2+ green soln [Fe(H 2 O) 6 ] 2+ green ppt* 2 [Fe(OH) 2 (H 2 O) 4 ] insoluble in xs Fe 3+ yellow/orange soln [Fe(H 2 O) 6 ] 3+ * 1 rust/brown ppt [Fe(OH) 3 (H 2 O) 3 ] insoluble in xs blood-red soln [Fe(SCN)(H 2 O) 5 ] 2- ion aq NaOH NH 3 SCN - thiocyanate * 1 [Fe(H 2 O) 6 ] 3+ is actually pale violet. The high charge density on the metal ion causes some deprotonation and the yellow-orange colour is actually due t o [Fe(OH)(H 2 O) 5 ] 2+ * 2 NB: Iron (II) hydroxide slowly oxidises to iron (III) hydroxide, so a rust/brown colour is observed after some time.

5. Chromium (III) and Manganese (II) Cr 3+ green soln [Cr(H 2 O) 6 ] 3+ green-blue ppt [Cr(OH) 3 (H 2 O) 3 ] soluble – green soln [Cr(OH) 6 ] 3- green-blue ppt [Cr(OH) 3 (H 2 O) 3 ] soluble – violet soln [Cr(NH 3 ) 6 ] 3+ Mn 2+ pink soln [Mn(H 2 O) 6 ] 2+ white ppt* [Mn(OH) 2 (H 2 O) 4 ] insoluble in xs ion aq NaOH NH 3 *NB: Manganese (II) hydroxide slowly oxidises to manganese (III) oxide, so the white (off-white) precipitate slowly turns brown/black. Chromium (VI) CrO 4 2- yellow soln Chromium (VII) Cr 2 O 7 2- orange soln aq Chrome alum KCr(SO 4 ) 2 violet crystals

6. Nickel (II) and Vanadium Ni 2+ green soln [Ni(H 2 O) 6 ] 2+ green ppt [Ni(OH) 2 (H 2 O) 4 ] insoluble in xs green ppt [Ni(OH) 2 (H 2 O) 4 ] soluble – blue soln [Ni(NH 3 ) 6 ] 2+ yellow soln [NiCl 4 ] 2- blue soln [Ni(edta)] 2- purple soln [Ni(en) 3 ] 2+ ion aq NaOH NH 3 conc HCl edta en Vanadium (II) V 2+ violet Vanadium (III) V 3+ green Vanadium (IV) VO 2+ blue Vanadium (III) VO 2 + yellow aq