10 questions🇬🇧English
💠 Transition Metal Complexes – A-level
Chemistry · A-level — practise ligands, shapes of complexes, colour, ligand substitution and the chelate effect.
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Questions
What type of bond forms between a ligand and the central metal ion in a complex?
Coordinate (dative covalent) bond
Ionic bond
Hydrogen bond
Metallic bond
20s
What is the shape of the complex ion [CoCl₄]²⁻?
Linear
Tetrahedral
Square planar
Octahedral
20s
Which of these ligands is bidentate?
Ammonia
Ethane-1,2-diamine
Chloride ion
EDTA⁴⁻
20s
Zinc is in the d-block but is not classed as a transition metal. Why?
Zinc atoms have no electrons in the d sub-level
Zinc cannot form any complex ions
Zinc only forms ions with a 3+ charge
Its only ion, Zn²⁺, has a full d sub-level
30s
Why does a solution containing [Cu(H₂O)₆]²⁺ ions appear blue?
It absorbs blue light as d electrons are excited
It absorbs red-orange light as d electrons are excited
It emits blue light as d electrons drop down
It reflects blue light off its split d orbitals
30s
Excess aqueous ammonia is added to [Cu(H₂O)₆]²⁺(aq). What is the formula of the deep blue complex formed?
[Cu(NH₃)₄(H₂O)₂]²⁺
[Cu(OH)₂(H₂O)₄]
[Cu(NH₃)₆]²⁺
[Cu(NH₃)₂(H₂O)₄]²⁺
30s
In the complex [Cr(C₂O₄)₃]³⁻, what are the oxidation state of chromium and its coordination number?
+3 and 3
+3 and 6
+6 and 6
+6 and 3
30s
Fe²⁺ ions catalyse the reaction between S₂O₈²⁻ and I⁻ ions. Which property of iron makes this possible?
Iron provides a surface for reactants to adsorb
Iron ions give the reactants more kinetic energy
Iron can change easily between the +2 and +3 states
Iron forms coloured complexes with iodide ions
30s
[Cu(H₂O)₆]²⁺ + 3en → [Cu(en)₃]²⁺ + 6H₂O. Why is this substitution so favourable?
Particles increase from 4 to 7, so entropy increases
Particles decrease from 7 to 4, so entropy increases
en lowers the activation energy of the reaction
Cu–N bonds are far stronger, so ΔH is very negative
60s
Cisplatin, [Pt(NH₃)₂Cl₂], is used as an anticancer drug. How does it work?
It bonds to N atoms on DNA bases, stopping replication
It oxidises DNA bases, breaking the double helix
Pt²⁺ forms ionic bonds with DNA phosphate groups
Its Cl⁻ ligands hydrogen bond to DNA base pairs
30s