Sub-shells, orbitals and electron configuration

This question is about ionisation energies.

Explain why beryllium is the element with the highest first ionisation energy in Group 2.

Give an equation, including state symbols, to show the process that occurs when the second ionisation energy of beryllium is measured.

Predict which element in Period 3 has the lowest second ionisation energy.

Figure 1 shows a plot of log₁₀(ionisation energy) for a Period 3 element.

The ionisation energies are measured in kJ mol^–1

Deduce the identity of this element.

Explain your answer.

Use Figure 1 to determine the third ionisation energy, in kJ mol^–1, of this element.

This question is about the chemistry of copper.

Deduce the number of unpaired electrons in a Cu²⁺ ion.

Describe how water acts as a ligand in the formation of [Cu(H₂O)₆]²⁺

A solution of sodium carbonate is added to a blue solution containing

State what is observed.

Give an equation for the reaction.

Equation

When a solution containing [Cu(H₂O)₆]²⁺ ions reacts with an excess of concentrated hydrochloric acid, a ligand exchange reaction occurs.

Blue Yellow

The shape and the colour of the [CuCl₄]^2– ion are different from the shape and the

Explain

• the shape of each complex ion and why these shapes are different

• how colour arises in complex ions

• why the [CuCl₄]^2– ion has a yellow colour, different from the blue colour of the

An excess of water, followed by an excess of concentrated aqueous ammonia, is added to a solution containing [CuCl₄]^2– ions.

State what is observed.

Give an equation for the overall change that occurs.

Equation

A solution contains M₂[Cu(C₂O₄)₂(H₂O)₂] where M is a metal.

A student does a titration to determine the identity of M.

• 2.52 g of solid M₂[Cu(C₂O₄)₂(H₂O)₂] are dissolved in dilute sulfuric acid.

• This solution is transferred to a volumetric flask and made up to 250 cm³ with dilute sulfuric acid.

• A 25.0 cm³ portion is pipetted into a conical flask.

• The mixture in the conical flask is heated to 60 °C and then titrated with 0.0200 mol dm^–3 KMnO₄ solution.

• Several titrations are done and the student’s results are shown in Table 3.

In this titration, only the C₂O₄^2– ions react with the MnO₄^– ions. 2 mol of MnO₄^– ions react with 5 mol of C₂O₄^2– ions.

Give an equation for the reaction between C₂O₄^2– ions and MnO₄^– ions in acidic solution.

Calculate the mean titre from the student’s results.

Calculate the M_r of M₂[Cu(C₂O₄)₂(H₂O)₂]

Identify M.

Draw the structure of two stereoisomers of the complex ion in M₂[Cu(C₂O₄)₂(H₂O)₂] and include the charge on each structure.

Structure 1
Structure 2

Which electron configuration represents an element that can have a maximum oxidation state of +5 in its compounds?

Which element has the highest third ionisation energy?

Which statement about chloride ions is correct?

This question is about metal chlorides.

Table 2 shows some enthalpy change data.

Use the data in Table 2 to calculate the molar enthalpy change when calcium chloride dissolves in water.

Molar enthalpy change
kJ mol^–1

Use your answer to Question 05.1 to deduce how the temperature changes when calcium chloride dissolves in water.

Explain why the enthalpy of hydration of fluoride ions is more negative than the enthalpy of hydration of chloride ions.

Figure 2 shows an incomplete Born–Haber cycle for calcium chloride.

Complete the Born–Haber cycle by writing the formulas of the missing species on each of the two blank lines.

Table 3 shows some enthalpy change data.

Use Figure 2 and data from Table 3 to calculate the second ionisation energy of calcium.

Second ionisation energy
kJ mol^–1

Explain why the second ionisation energy of calcium is greater than the first ionisation energy of calcium.

Table 4 shows lattice enthalpies based on a perfect ionic model and lattice enthalpies from Born–Haber cycles for three metal chlorides.

Discuss the values in Table 4.

In your answer you should

compare the three values based on a perfect ionic model

compare the values based on a perfect ionic model to the values from a Born–Haber cycle for each compound.

This question is about complexes containing the aluminium ion.

Give the electron configuration of the Al³⁺ ion.

When anhydrous aluminium sulfate, Al₂(SO₄)₃, is added to water a solution forms that contains the complex aluminium ion, [Al(H₂O)₆]³⁺

Give the equation for the reaction.

Explain why the solution containing [Al(H₂O)₆]³⁺ is acidic.

State why the concentration of aluminium sulfate solution can not be determined by

An excess of aqueous ammonia is added to a solution containing [Al(H₂O)₆]³⁺

Give an ionic equation for the reaction and state one observation.

Equation

An excess of dilute sulfuric acid is added to the products of the reaction in Question 07.5

Identify the aluminium species produced.

Figure 3 shows the structure of the EDTA^4– ion.

Atoms of two different elements in EDTA^4– can form co-ordinate bonds with an aluminium ion.

On Figure 3, draw circles around the atoms of two different elements that would link to an aluminium ion by a co-ordinate bond.

Hydrated aluminium sulfate, Al₂(SO₄)₃.xH₂O, is soluble in water.

The relative formula mass and value of x can be found from a titration experiment.

Aqueous [Al(H₂O)₆]³⁺ ions react to form a stable complex when treated with an excess

The excess of EDTA^4– ions is determined by titration with ZnSO₄ solution.

• Dissolve 1.036 g of Al₂(SO₄)₃.xH₂O in distilled water and make up to 250 cm³

• Add 25.0 cm³ of this solution to 50.0 cm³ of a solution containing EDTA^4– ions of concentration 0.0100 mol dm^–3

• Determine the excess of EDTA^4– ions by titrating with ZnSO₄ solution in the presence of an indicator.

The excess of EDTA^4– ions requires 18.00 cm³ of 0.0105 mol dm^–3 ZnSO₄ solution to

The equations for the reactions are

Use the information given to calculate the M_r of Al₂(SO₄)₃.xH₂O

Give your answer as an integer.

There are no questions on this page

Which atom in the ground state contains at least one unpaired p electron?

Which ionisation needs less energy than this process?

Which statement is correct about the Group 1 elements?

Which statement about chloride ions is not correct?

Which has the electron configuration of a noble gas?

This question is about Period 3 elements.

Figure 2 shows the second ionisation energies of some elements in Period 3.

Draw a cross (x) on Figure 2 to show the second ionisation energy of silicon.

Identify the element in Period 3, from sodium to argon, that has the highest second ionisation energy.

Give an equation, including state symbols, to show the process that occurs when the second ionisation energy of this element is measured.

If you were unable to identify the element you may use the symbol Q in your equation.

Equation

Explain why the atomic radius decreases across Period 3, from sodium to chlorine.

Identify the element in Period 3, from sodium to chlorine, that has the highest electronegativity.

Phosphorus burns in air to form phosphorus(V) oxide. Give an equation for this reaction.

A student does an experiment to determine the percentage of copper in an alloy.

The student

• reacts 985 mg of the alloy with concentrated nitric acid to form a solution (all of the copper in the alloy reacts to form aqueous copper(II) ions)

• pours the solution into a volumetric flask and makes the volume up to 250 cm³ with distilled water

• shakes the flask thoroughly

• transfers 25.0 cm³ of the solution into a conical flask and adds an excess of potassium iodide

• uses exactly 9.00 cm³ of 0.0800 mol dm^–3 sodium thiosulfate (Na₂S₂O₃) solution to react with all the iodine produced.

The equations for the reactions are

Calculate the percentage of copper by mass in the alloy.

Give your answer to the appropriate number of significant figures.

Suggest two ways that the student could reduce the percentage uncertainty in the measurement of the volume of sodium thiosulfate solution, using the same apparatus as this experiment.

State the role of iodine in the reaction with sodium thiosulfate.

Give the full electron configuration of a copper(II) ion.

Copper(I) iodide is a white solid.

Explain why copper(I) iodide is white.

Iodine vaporises easily.

Calculate the volume, in cm³, that 5.00 g of iodine vapour occupies at 185 °C and 100 kPa

The gas constant R = 8.31 J K^–1 mol^–1

Give your answer to 3 significant figures.

Which atom has the greatest first ionisation energy?

This question is about s-block metals.

Give the full electron configuration for the calcium ion, Ca²⁺

Explain why the second ionisation energy of calcium is lower than the second ionisation energy of potassium.

Identify the s-block metal that has the highest first ionisation energy.

Give the formula of the hydroxide of the element in Group 2, from Mg to Ba, that is least soluble in water.

A student added 6 cm³ of 0.25 mol dm^–3 barium chloride solution to 8 cm³ of 0.15 mol dm^–3 sodium sulfate solution. The student filtered off the precipitate and collected the filtrate.

Give an ionic equation for the formation of the precipitate. Show by calculation which reagent is in excess. Calculate the total volume of the other reagent which should be used by the student so that the filtrate contains only one solute.

Total volume of other reagent

A sample of strontium has a relative atomic mass of 87.7 and consists of three

State why the isotopes of strontium have identical chemical properties. Calculate the percentage abundance of the⁸⁸Sr isotope in this sample.

Why isotopes of strontium have identical chemical properties

A time of flight (TOF) mass spectrum was obtained for a sample of barium that

Identify the ion with the longest time of flight.

A¹³⁷Ba⁺ ion travels through the flight tube of a TOF mass spectrometer with a

The Avogadro constant, L = 6.022 × 10²³ mol^–1

Calculate the length of the flight tube in metres. Give your answer to the appropriate number of significant figures.