Shapes of complex ions and isomerismAQA A-Level Chemistry: Flashcards

What these 13 flashcards ask

What shape and bond angle do complexes with six small ligands have?
Give two ligands that commonly form octahedral complexes.
What shape do complexes with large ligands like Cl⁻ commonly form?
Give an example of a tetrahedral complex.
What is the shape and bond angle of a square planar complex?
What is the shape of [Ag(NH₃)₂]⁺?
Where is [Ag(NH₃)₂]⁺ used?
What is cis-trans isomerism?
Which complexes show cis-trans isomerism?
What is optical isomerism?
Which complexes show optical isomerism?
Which isomer of Pt(NH₃)₂Cl₂ is cisplatin?
Why do tetrahedral complexes not show cis-trans isomerism?

Exam questions on Shapes of complex ions and isomerism

A student compares the shapes of four complex ions: [Ni(H₂O)₆]²⁺, [CoCl₄]²⁻, [Ag(NH₃)₂]⁺ and [Pt(NH₃)₂Cl₂].
Explain why [Ni(H₂O)₆]²⁺ is octahedral but [CoCl₄]²⁻ is tetrahedral.2 marks
The octahedral complex ion [Co(NH₃)₄Cl₂]⁺ exists in two forms, one green and one violet. The complex ion [Ni(en)₃]²⁺, where en is the bidentate ligand H₂NCH₂CH₂NH₂, also exists in two forms.
State what is meant by optical isomers and explain why [Ni(en)₃]²⁺ shows optical isomerism.2 marks
Platinum(II) forms the neutral complex Pt(NH₃)₂Cl₂, which has a square planar shape and exists as two isomers. One of them, cisplatin, is used as an anticancer drug.
State the shape of the complex, its co-ordination number and the arrangement of the chloride ligands in cisplatin.3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).