Transition Metals Flashcards
What is the colour of the solution formed by the [Fe(H2O)6]3+ complex
Purple Solution that appears brown.
What is the colour of the solution formed by the [Fe(H2O)6]2+ complex
Green Solution
What is the colour of the solution formed by the[Cu(H2O)6]3+ complex
Blue Solution
What is the colour of the solution formed by the [Al(H2O)6]3+ complex
Colourless Solution
What is the shape of [Fe(H2O)6]3+ complex
Octahedral
What is the shape of [Fe(Cl)4]2- complex
tetrahedral
Why is [Fe(Cl)4]2- tetrahedral
The Cl- ions are too big to fit more than 4 around a transition metals
What shape of complex does Ag+ form?
Linear
What is the formula of the platin complex?
Pt(NH3)2(Cl)2
What is the shape of the cisplatin complex and what is the oxidation state of Pt in the complex
Square Planar - Pt2+
State the two bidentate ligands
NH2CH2CH2NH2 and C2O42-
Give the formula of the complex formed between Cu2+ and C2O42-
[Cu(C2O4)3]4-
Draw the complex of Ni2+ and NH2CH2CH2NH2
Which type of isomerism does the following complex display?
Cis -
Which type of isomerism does the following complex display?
Trans isomerism
Give an example of a multidentate ligand.
EDTA4-
Define chelate effect.
The substitution of a monodentate ligand for a bi or multidentate ligand to form a more stable complex.
What is the heterogeneous catalysist in the Contact process
V2O5
What is the heterogeneous catalyst used in the Haber process
Solid Fe (Iron)
Define autocayalysis
When a reaction is catalysed by a product of that reaction
When balancing half equations what species should MnO4- be converted to?
Mn2+
When balancing half equations what species should (C2O4)2- be converted to?
CO2
When balancing half equations what species should (Cr2O7)2- be converted to?
Cr3+
When balancing half equations what species should (S2O8)2- be converted to?
(SO4)2-
Define heterogeneous catalysis
where the catalyst is in a different phase to the reactants
Define homogeneous catalysis
where the catalyst is in the same phase as the reactants
Describe the 3 steps of heterogeneous catalysis
(1)Reactants** adsorb** onto the surface of the catalyst on an active site.
(2) Reaction occurs on the surface of the catalyst
(3) Products desorb from the surface if the catalyst
What happens to a catalyst when it is poisoned?
- Impurities can block the active sites.
- This prevents the reactants from adsorbing
- Purifying the reactants is the best way to prevent poisoning.
What is the equation for the energy difference between d orbitals?
∆E = hf
Where ∆E = Change in Energy
h = Planck Constant 6.626x10-34
f = Frequency of Light (Hz)
∆E = hc/l
Where ∆E = Change in Energy
h = Planck Constan
In terms of electrons, explain why an aqueous solution of cobalt(II) sulfate has a red colour.
(Blue) light is absorbed (from incident white light)
Due to electrons moving to higher levels/electrons excited
Red light (that) remains (is transmitted)
With reference to electrons, explain why aqueous copper(II) ions are blue.
red light absorbed
d electrons excited / promoted
or d electrons move between levels / orbitals
the colour observed is the light transmitted
Explain why complexes formed from transition metal ions are coloured.
M1 absorb (some) wavelengths/frequencies/colours/energies of (visible) light
M2 to promote/excite electrons in d-orbitals
M3 remaining wavelengths/frequencies/colours/energies of (visible) lighttransmitted (to give colour seen)
What’s the definition of a transition metal?
A Transition Element is one which forms at least one stable ion with a partially filled d sub-shell
Why is Sc not a Transition Metal?
Sc3+ is the only ion formed
The d subshell is empty
Why is Zn not a Transition Metal?
Zn 2+ is the only ion formed
The d subshell is full
What is the electron configuration of Cr?
1s2 2s2 2p6 3s2 3p6 4s1 3d5
What is the electron configuration of Cu?
1s2 2s2 2p6 3s2 3p6 4s1 3d10
What are the 4 characteristic properties of Transition Metals?
Complex Ions
Coloured Ions
Catalytic Properties
Variable Oxidation States
Define a bidentate ligand
A bidentate ligand has two atoms that each donate a lone pair of electrons
Define a complex ion
A central atom or ion surrounded by ligands (that form co-ordinate bonds)
Which square planar complex is used as a chemotherapy agent?
Cis platin
Which linear complex is the active agent in Tollen’s reagent?
Describe the structure of haemoglobin
How is oxygen transported in the blood?
O2 forms a co-ordinate bond to Fe2+ in haemoglobin enabling oxygen to be transported in the blood
Why is carbon monoxide toxic?
CO is toxic because CO bonds more strongly to the Fe2+ in haemoglobin.
This prevents O2 from bonding to the Fe2+, causing suffocation
What can change the colour of a complex ion?
Complex ions (transition metal ions) change colour when the energy difference between d orbitals is altered.
This can occr when there is:
- Change in ligands
- Change in oxidation state of the metal
- Change in the coordination number of the complex
How can you determine the unknown concentration of a transition metal ion solution?
By Colorimetry
Describe how colorimetry can be used to determine the concentration of a coloured complex.
Measure the absorbance for a range of (known) concentrations
Plot graph of absorbance v concentration/calibration curve (of absorbance v concentration)
Measure absorbance of the coloured complex and find concentration from graph
Show how V2O5 acts as a heterogenous catalyst in the Contact Process
Step 1 – Sulfur Dioxide is oxidised to Sulfur Trioxide
SO2(g) + V2O5(s) –> SO3(g) + V2O4(s)
Step 2 – The Vanadium (IV) Oxide is then converted back to Vanadium (V) Oxide with oxygen.
2V2O4(s) + O2(g) –> 2V2O5(s)
What are the species that need balancing to give an example of homogeneous catalysis
Overall: S2O82- + 2 I- → 2 SO42- + I2
Step 1: 2 Fe2+ + S2O82- → 2 SO42- + 2 Fe3+
Step 2: 2 Fe3+ + 2 I- → 2 Fe2+ + I2
What are the equations for autocatalysis?
Overall:
2MnO4-(aq) + 16H+(aq) + 5C2O42-(aq) –> 2Mn2+(aq) + 8H2O(l) + 10CO2(g)
Step 1
4 Mn2+ + MnO4– + 8 H+ → 5 Mn3+ + 4 H2O
Step 2
2 Mn3+ + C2O42– → 2 Mn2+ + 2 CO2
