Developing Metals | OCR A-Level Chemistry B (Salters) (H433)

Developing Metals

304 questions
18 subtopics
The ten storylines, examined across all three papers
Component 01, Component 02 and Component 03

The storyline that carries electrochemistry and the transition elements: redox titrations, balancing half-equations in acid, electrochemical cells and standard electrode potentials, rusting, and the complexes, colours and catalysis of the d-block..

It covers manganate(VII) titrations and their calculations, thiosulfate titrations, recording results and good technique, shapes of complexes and coordination number, balancing redox equations involving acid-base reactions, simple electrochemical cells, action of an electrochemical cell, standard electrode potentials and calculating E°cell, rusting and how it is prevented, transition metals: definition, oxidation states and colours, d-block electron configurations of the atoms and their ions, why transition metals show variable oxidation states, ligands and complex ions, coordinate bonding and what makes a ligand, bidentate and multidentate ligands, and finding a complex's formula, reactions of Fe2+, Fe3+ and Cu2+ with hydroxide and ammonia, catalytic activity of transition metals, origin of colour in transition metal complexes and colorimetry.

Sample questions from Developing Metals

Answer each one closed book first, then open the answer.

Manganate(VII) titrations and their calculations

Which acid is used to acidify a manganate(VII) titration, and why is hydrochloric acid avoided?

Show the answer
Dilute sulfuric acid is used, because manganate(VII) would oxidise the chloride ions of hydrochloric acid and the titre would be too large.
Shapes of complexes and coordination number

What are the bond angles in an octahedral complex?

Show the answer
Every neighbouring pair of ligands is separated by 90°, and each ligand is 180° from the one directly opposite it through the metal.
Simple electrochemical cells

What temperature and pressure are used as standard for electrode potential measurements?

Show the answer
The temperature is 298 K and the pressure is 100 kPa.
Standard electrode potentials and calculating E°cell

What does a strongly negative standard electrode potential tell you about the species involved?

Show the answer
The reduced form releases electrons readily, so it is a good reducing agent, while the oxidised form is a poor oxidising agent.
Transition metals: definition, oxidation states and colours

What is the colour of an aqueous iron(III) solution?

Show the answer
The hexaaqua ion is pale violet, although in practice such solutions usually look yellow-brown.
Why transition metals show variable oxidation states

What is the electron configuration of the Sc³⁺ ion?

Show the answer
It is 1s² 2s² 2p⁶ 3s² 3p⁶, with no d electrons at all.
Coordinate bonding and what makes a ligand

Why are transition metal ions particularly good at accepting lone pairs from ligands?

Show the answer
They are small and highly charged and have vacant d and s orbitals available to accept electron pairs.
Reactions of Fe2+, Fe3+ and Cu2+ with hydroxide and ammonia

What happens to these three precipitates when excess sodium hydroxide is added?

Show the answer
Nothing further happens, as all three hydroxides remain as precipitates in excess sodium hydroxide.

The 18 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
Manganate(VII) titrations and their calculations	Recall questions on why manganate(VII) is self-indicating, which acid is used and why the others are not, and the calculations with iron(II), ethanedioate and peroxide.	14
Thiosulfate titrations, recording results and good technique	Recall questions on the copper(II) and iodine route, when starch is added, concordant titres, and why the burette but not the flask is rinsed with solution.	12
Shapes of complexes and coordination number	Recall questions on why coordination number is not always the ligand count, and the shapes and bond angles for four and six coordination.	19
Balancing redox equations involving acid-base reactions	Recall questions on the manganate(VII) and dichromate(VI) half-equations, why the electron counts are what they are, and combining halves into a full equation.	21
Simple electrochemical cells	Recall questions on setting up a metal half-cell, the salt bridge, the high-resistance voltmeter, and the standard conditions.	20
Action of an electrochemical cell	Recall questions on which electrode is negative and why, the half-equation at each, and what happens to the electrode masses and the solution as the cell runs.	18
Standard electrode potentials and calculating E°cell	Recall questions on the definition and the hydrogen reference, what a positive or negative value means, and calculating E°cell to test feasibility.	16
Rusting and how it is prevented	Recall questions on the two half-equations, what rust is, and how galvanising, barrier methods and cathodic protection each work.	10
Transition metals: definition, oxidation states and colours	Recall questions on what defines a transition element, the colours of the common aqueous ions, and the disproportionation of copper(I).	21
d-block electron configurations of the atoms and their ions	Recall questions on which sub-shell fills first, which electrons are lost first, and the configurations of chromium, copper and the common ions.	12
Why transition metals show variable oxidation states	Recall questions on the closeness of the 4s and 3d energies, why the s-block shows one state only, and which arrangements carry extra stability.	11
Ligands and complex ions	Recall questions on the three common monodentate ligands, why complexes carry the charges they do, and working out a complex's charge.	22
Coordinate bonding and what makes a ligand	Recall questions on what a coordinate bond is, which atom donates, why methane cannot be a ligand, and how the bond compares with an ordinary covalent one.	10
Bidentate and multidentate ligands, and finding a complex's formula	Recall questions on the ethanedioate ion and EDTA, how many bind to one metal ion, and deducing a formula from a mole ratio.	13
Reactions of Fe2+, Fe3+ and Cu2+ with hydroxide and ammonia	Recall questions on the colour and identity of each precipitate, the ionic equations, why the iron(II) precipitate darkens, and which redissolve in excess ammonia.	22
Catalytic activity of transition metals	Recall questions on how a variable oxidation state allows catalysis, the two steps of the iodide and peroxodisulfate route, and adsorption strength.	20
Origin of colour in transition metal complexes	Recall questions on d orbital splitting, why some ions are colourless, and how ligand, oxidation state and coordination number change the colour.	21
Colorimetry	Recall questions on choosing a filter, the blank, building and using a calibration line, and why a sample above the range must be diluted.	22

Developing Metals is 304 of the 3,430 questions in the guide.Get the guide, £8

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.