Transition Metals Flashcards
transition metal definition
an element with an incomplete d sub-shell in either its atoms or one or more of its common ions
4 general properties of transition metals
variable oxidation states
catalytic action
coloured compounds
form complexes
transition metals with different e- structures
Cu, Cr
ligand
molecule or ion that bonds to metals by a coordinate bond
complex
metal ion with coordinately bonded ligands
coordination number
number of coordinate bonds from ligands to metal ion
lewis acid
lone pair acceptor
lewis base
lone pair donor
chloride ligand
:Cl-
hydroxide ligand
:OH-
cyanide ligand
:CN-
water ligand
H2O:
ammonia ligand
:NH3
1,2-diaminoethane ligand
and name
CH2–CH2
H2N:/</sup>:NH2
(en)
ethanedioate ligand
[ O O
\C–C//
-O:/</sup>:O- ] 2-
ethanedioate ligand formula
(Cr2O4)2-
Which metal ions form linear complexes
Ag+
which metal ions form square planar complexes
Pt2+ Ni2+
type of complexes with tetrahedral shape
often contain Cl- ligands
linear complex example
[Ag(NH3)2]+
square planar complex example
[PtCl4]2-
tetrahedral complex example
[CuCl4]2-
octahedral complex example
[Cu(H2O)6]2+
3 things to include when asked to show bonding and structure of metal complexes
lone pairs, arrows for coordinate bonds, [] charge
geometric isomerism in metal complexes
2 of the same ligand square planar (E/Z) or octahedral
optical isomerism in metal complexes
three bidente ligands in an octahedral complex
3 uses of transition metal complexes
Tollen’s reagent
Cisplatin
Haemoglobin
Tollen’s reagent use
testing for aldehydes
Cisplatin use
anti-cancer drug
Haemoglobin use
carries oxygen around the body
why are transition metal complexes coloured
electrons absorb frequencies of light
d electrons are excited to a higher energy level
colour seen is colour (frequencies) which are not absorbed
2 factors affecting the colour of transition metal complexes
oxidation state of metal
co-ordination number
why can the same metal ions have different coordination numbers
when ligands are smaller, more of them can fit around the central metal ion
how can the concentration of dilute tranistion metal complex ions solutions be found
coloroimetry
make up a set of concentrations
chose calorimeter filter, opposite to the colour of the ion
plot graph of absorbance vs concentraion
find corresponding conc. for absorbance of unkown solution from graph
meaning of terms in ∆E=hν
E - energy difference between d orbitals
h - Planck’s constant
ν - frequency of light
EDTA4-
ligand with 6 lone pairs, forming an octahedral complex
Tollen’s reagent formula
[Ag(NH3)2]+
Cisplatin formula
Pt(NH3)2Cl2
Haemoglobin structure
Fe2+ central ion
with multidente porphyrin, globin and O2/H2O attached