D block elements - Have highest energy electrons in a d sub-level
Transition element - Form stable ions with an incomplete d subshell
D block ions lose 4s electrons before 3d
- They make good catalysts
- They have variable oxidation states
- They form coloured compounds
Complex ions - A transition metal ion bonded to one or more ligands by dative covalent bonds.
Ligand - A molecule or ion that can donate a lone pair of electrons to a central metal ion to form a dative covalent bond.
Unidentate ligand - No. of coordinate bonds are equal to them number of ligands
- Can only have 4 Cl because Cl is a bigger molecule so can't fit as many around the metal ion.
- Sometimes get square planar such as Platin. Cis platin is used to treat cancer as it binds irreversibly with DNA so it can't replicate
Bidentate ligand - A ligand that contains two atoms that donate lone pairs.
- An example of a multidentate ligand is EDTA, the EDTA ion forms all 6 coordinate bonds. EDTA has a 4- charge.
Copper Suplhate solution: (Blue solution to blue precipitate)
Cu 2+ + 2OH- --------> Cu(OH)2
Cobalt (II) solution: (Pink solution to blue precipitate)
Co 2+ + 2OH- --------> Co(OH)2
Iron (II) sulphate solution: (Pale green solution to green precipitate)
Fe 2+ + 2OH- -------> Fe(OH)2
Iron (III) sulphate solution: (Brown/Orange solution to brown-orange precipitate)
Fe 3+ + 3OH- ----------> Fe(OH)3
Copper (II) solution with ammonia: (blue solution to sark blue solution)
[Cu(H2O)6]2+ + 4NH3 -------->[Cu(H2O)2(NH3)4]2+ + 4H2O
Copper (II) solution with Chloride: (blue solution to green/yellow solution)
[Cu(H2O)6]2+ +4Cl- --------> [CuCl4]2- + 6H2O
Colbalt (II) chloride solution: (pink solution to blue solution)
[Co(H2O)6]2+ + 4Cl- --------> [CoCl4]2- + 6H2O
- If electrons on the left its reduction.
- If electrons on the right its oxidation
- Balance oxygen by adding H2O
- Balance H by adding H+
Adding half equations together:
- Balance electrons in each equation to remove them. Can't be present in the overall equation.
- Times everything in the equation by the number needed.
- If needed cancel out any H2O or H+
Ionic equations using oxidation numbers:
- Balance atoms
- Work out oxidation number changes
- Use the change to balance out opposite compounds
- Balance any O and H
- Check atoms and charges balance
- Simplify if needed