Deduce the period and group number of element E.

Deduce the number of valence electrons and the block of the periodic table to which element E belongs.

Describe the trend in atomic radius across period 3 from sodium to chlorine.

Explain the trend in atomic radius across period 3.

State the general trend in electronegativity across period 3 from left to right.

Write the balanced equation for the reaction of potassium with water.

Explain why chlorine displaces iodide ions from aqueous potassium iodide, but iodine does not displace chloride ions from aqueous potassium chloride.

Write the equation for the reaction of sodium oxide with water.

Write the equation for the reaction of sulfur trioxide with water.

Outline how the acid-base character of the oxides changes across period 3 from sodium to sulfur.

Deduce the period and group of element B from its electron configuration.

Identify the block and broad classification of element C.

Suggest why element D is classified as a metalloid rather than simply as a metal or non-metal.

State the gas produced in the reactions.

Describe how the reactivity changes from lithium to potassium using the data.

Explain the change in reactivity down group 1.

Deduce the oxidation state of hydrogen in $CaH_2$ and oxygen in $Na_2O_2$.

Deduce the oxidation state of sulfur in $SO_4^{2-}$ and give the systematic name of this oxyanion using a Roman numeral.

State the general trend in first ionization energy across period 2.

Explain why the first ionization energy of boron is lower than that of beryllium.

Explain why the first ionization energy of oxygen is lower than that of nitrogen.

Define the term transition element.

Explain why zinc is not usually classified as a transition element.

State one characteristic property commonly shown by transition elements that is linked to incomplete d-sublevels.

State the condensed electron configuration of a chromium atom.

Deduce the electron configuration of $Cr^{3+}$.

Deduce the electron configuration of $Fe^{2+}$, given that $Fe$ is $[Ar]4s^23d^6$.

State which sublevel loses electrons first when first-row transition metal atoms form ions.

Calculate the frequency of the light absorbed.

Deduce the colour observed if the absorbed light is orange-red.

State one factor that can affect the colour of a transition metal complex.

Describe the trend in atomic radius across the period shown.

Explain the trend in atomic radius across the period.

Use the data to suggest the element in the graph with the strongest attraction for bonding electrons, giving a reason.

Identify one mixture in which a displacement reaction occurs.

Write the ionic equation for the reaction between chlorine and bromide ions.

Use the observations to deduce the order of decreasing reactivity of the three halogens.

Deduce the oxidation state of hydrogen in sodium hydride, $NaH$.

Deduce the oxidation state of oxygen in hydrogen peroxide, $H_2O_2$.

Deduce the oxidation state of nitrogen in $NO_3^-$.

Explain why chlorine has oxidation state zero in $Cl_2$.

Using the data, identify the element that is d-block but is not normally classified as a transition element.

Explain the identification in part (a) using electron configurations.

Evaluate one argument for including scandium as a transition element, based on the data.

State what is meant by successive ionization energies.

Explain why vanadium can form several oxidation states.

Deduce the electron configuration of $V^{3+}$, given that $V$ is $[Ar]4s^23d^3$.

Outline how the calibration graph is used to determine the concentration of the unknown solution.

Explain why a wavelength strongly absorbed by the complex is chosen for the colorimeter.

Classify sodium oxide and sulfur dioxide as basic, acidic or amphoteric oxides.

Write an equation for the reaction of sodium oxide with water.

Explain why the data support the idea that metallic and non-metallic properties form a continuum across period 3.

Describe the overall trend in first ionization energy across period 2.

Explain the discontinuity between beryllium and boron.

Explain the discontinuity between nitrogen and oxygen.

State the colour of light mainly absorbed by the complex.

Determine the wavelength at maximum absorbance from the spectrum, in metres.

Calculate the frequency of light at maximum absorbance.

Explain why absorption of this light gives rise to the observed colour.

Deduce the electron configuration of $Fe^{3+}$ from $Fe: [Ar]4s^2 3d^6$.

Deduce the electron configuration of $Cu^{2+}$ from $Cu: [Ar]4s^1 3d^{10}$.

Outline the rule used to decide which electrons are removed first when first-row transition metal ions form.

Using the data, suggest why copper(II) compounds are more likely to be coloured than zinc(II) compounds.

Compare the classifications of elements B and C as metal, metalloid or non-metal, using their positions in the periodic table.

Hydrogen is often placed above group 1. Suggest why this placement does not make hydrogen an alkali metal.

Magnesium commonly forms $Mg^{2+}$. Suggest why the ionic radius of $Mg^{2+}$ is smaller than the atomic radius of Mg.

Explain why the oxidation state of chlorine in $Cl_2$ is zero.

Discuss how the organization of the periodic table can help chemists predict properties of undiscovered elements.

State what is meant by successive ionization energies.

Use the data to identify which element, X or Y, is more likely to be a transition element.

Explain how the successive ionization energy data account for variable oxidation states in X.

Deduce the electron configuration of $V^{3+}$ from the neutral atom configuration $V: [Ar]4s^2 3d^3$.

Use the calibration graph to determine the concentration of the unknown solution.

Explain why the wavelength selected should be close to the wavelength of maximum absorbance.

Suggest one source of systematic error in this colorimetric method.

The ligand around the metal ion is changed and the absorption maximum shifts to a shorter wavelength. Explain what this indicates about the split d-sublevels.

Deduce whether aqueous bromine reacts with aqueous iodide ions and write the ionic equation if a reaction occurs.

Evaluate the use of simulations rather than direct practical work for these reactivity comparisons.

Explain, in terms of bonding, why metal oxides tend to be basic while non-metal oxides tend to be acidic.

Discuss how the behaviour of $Al_2O_3$ supports the idea that metallic and non-metallic properties form a continuum.

Discuss how these discontinuities provide evidence for the existence of energy sublevels.

Explain how incomplete d sublevels account for three characteristic properties of transition element compounds.

Explain why variable oxidation states are common among transition elements.

Using the graph, suggest why $V^{5+}$ is plausible but $Ca^{5+}$ is not.

The absorbance of a diluted sample corresponds on the calibration curve to $1.60 \times 10^{-3}\ \text{mol dm}^{-3}$. The original sample was diluted by transferring $10.0\ \text{cm}^3$ into a $100.0\ \text{cm}^3$ volumetric flask and making up to the mark. Calculate the concentration of the original sample.

Evaluate two ways to improve or check the reliability of the colorimetry result.

Discuss why iron can show both catalytic behaviour and variable oxidation states.