Structure 1. Models of the particulate nature of matter

1.1 Introduction to the particulate nature of matter

1.2 The nuclear atom

1.3 Electron configurations

1.4 The mole

1.5 Ideal gases

Structure 2. Models of bonding and structure

2.1 The ionic model

2.2 The covalent model

2.3 The metallic model

2.4 From models to materials

Structure 3. Classification of matter

3.1 The periodic table

3.2 Functional groups: Organic compounds

Reactivity 1. What drives chemical reactions?

1.1 Measuring enthalpy changes

1.2 Energy cycles

1.3 Energy from fuels

Reactivity 2. How much, how fast and how far?

2.1 Amount of chemical change

2.2 Rate of chemical change

2.3 Extent of chemical change

Reactivity 3. What are the mechanisms of chemical change?

3.1 Proton transfer reactions

3.2 Electron transfer reactions

3.3 Electron sharing reactions (Radicals)

3.4 Electron-pair sharing reactions

IB Chemistry SL 3.1 The periodic table Question Bank

[Maximum number: 1]

In order to provide safe drinking water, a water supply is often treated with disinfectants, which aim to inactivate disease-causing bacteria in the water.

To compare the effectiveness of different disinfectants, a CT value is used as a measure of the dosage of disinfectant needed to achieve a certain level of inactivation of specific bacteria.

CT value $\left(\mathrm{mg} \mathrm{min} \mathrm{dm}^{-3}\right)=\mathrm{C}\left(\mathrm{mg} \mathrm{dm}^{-3}\right) \times \mathrm{T}(\mathrm{min})$ concentration contact time
of disinfectant with water

(a)

The table below compares the CT values of different disinfectants necessary to achieve 99 % inactivation of two types of bacteria, listed as A and B.

[ 1 ]

(i)

Deduce the oxidation state of chlorine in the following disinfectants.

HOCl:
$\mathrm{ClO}_{2}:$

[ 1 ]

[Maximum number: 5]

Physical properties of elements vary according to atomic number. Sections 6 to 9 of the data booklet list some of these properties.

Melting points and boiling points of elements 1 to 95

(a)

Deduce, giving a reason, the group of elements in the periodic table most likely to undergo sublimation.

[ 2 ]

(b)

(i)

Describe the density trend across periods 4 and 5 of the periodic table.

Density of elements 1 to 95 at 298 K

[ 1 ]

(ii)

Suggest, with a reason, whether the lanthanoids or actinoids of the f-block would have the higher density.

[ 1 ]

(iii)

Sketch how the first ionization energies of elements vary with their atomic radius.

[ 1 ]

[Maximum number: 3]

There are many oxides of silver with the formula $\mathrm{Ag}_{\mathrm{x}} \mathrm{O}_{\mathrm{y}}$ . All of them decompose into their elements when heated strongly.

(a)

(i)

Some oxides of period 3, such as $\mathrm{Na}_{2} \mathrm{O}$ and $\mathrm{P}_{4} \mathrm{O}_{10}$ , react with water. A spatula measure of each oxide was added to a separate $100 \mathrm{~cm}^{3}$ flask containing distilled water and a few drops of bromothymol blue indicator.
The indicator is listed in section 22 of the data booklet.
Deduce the colour of the resulting solution and the chemical formula of the product formed after reaction with water for each oxide.

[ 3 ]

[Maximum number: 5]

Chlorine undergoes many reactions.

(a)

(i)

State, giving a reason, whether the chlorine atom or the chloride ion has a larger radius.

[ 1 ]

(ii)

Outline why the chlorine atom has a smaller atomic radius than the sulfur atom.

[ 2 ]

(b)

2.67 g of manganese(IV) oxide was added to $200.0 \mathrm{~cm}^{3}$ of $2.00 \mathrm{moldm} \mathrm{m}^{-3} \mathrm{HCl}$ .

\mathrm{MnO}_{2}(\mathrm{~s})+4 \mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{Cl}_{2}(\mathrm{~g})+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{l})+\mathrm{MnCl}_{2}(\mathrm{aq})

[ 2 ]

(i)

State the oxidation state of manganese in $\mathrm{MnO}_{2}$ and $\mathrm{MnCl}_{2}$ .
$\mathrm{MnO}_{2}:$ $\mathrm{MnCl}_{2}$ :

[ 2 ]

[Maximum number: 5]

The graph shows the variation of the first ionization energy with atomic radius for periods 2, 3 and 4 of the periodic table, with the d-block elements omitted.

(a)

Annotate the graph with an additional data point, marked with a cross ( X ), for scandium. Use sections 9 and 10 of the data booklet.

[ 1 ]

(b)

Suggest why there might be a link between the two variables in the graph.

[ 1 ]

(c)

The graph shows a relationship between first ionization energy and atomic radius.

[ 3 ]

(i)

State the type of relationship between the variables.

[ 1 ]

(ii)

Compare and contrast the trends shown by the different periods.

[ 2 ]

[Maximum number: 2]

Phosphorus is an element that is an essential part of the biological molecules involved in both respiration and photosynthesis.

(a)

(i)

Explain why the first ionization energy decreases as you descend group 15 from nitrogen to bismuth.

[ 2 ]

[Maximum number: 6]

Graphs showing the first ionization energy and first electron affinity of the elements in period 2 of the periodic table are shown.

First ionization energy

First electron affinity

(a)

First ionization energy tends to increase across the period. Explain the decrease in first ionization energy from beryllium to boron.

[ 2 ]

(b)

Suggest one reason for a positive value for the first electron affinity for nitrogen.

[ 1 ]

(c)

Suggest reasons why noble gases have the largest first ionization energy and largest positive first electron affinity in their period.

Largest first ionization energy:

Largest positive first electron affinity:

[ 2 ]

(d)

Suggest, giving one reason, how the first electron affinity of xenon compares with that of neon.

[ 1 ]

[Maximum number: 4]

Iron may be extracted from iron (II) sulfide, FeS.

(a)

Justify why sulfur is classified as a non-metal by giving two of its chemical properties.

[ 2 ]

(b)

Iron (II) sulfide, FeS , is ionically bonded.

[ 1 ]

(i)

Outline, in terms of their electronic structures, why the ionic radius of the sulfide ion is greater than that of the oxide ion.

[ 1 ]

(c)

The first step in the extraction of iron from iron (II) sulfide is to roast it in air to form iron (III) oxide and sulfur dioxide.

[ 1 ]

(i)

Deduce the change in the oxidation state of sulfur.

[ 1 ]

[Maximum number: 2]

Ethane-1,2-diol, $\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{OH}$ , has a wide variety of uses including the removal of ice from aircraft and heat transfer in a solar cell.

(a)

Determine the average oxidation state of carbon in ethene and in ethane-1,2-diol.

Ethene:

Ethane-1,2-diol:

[ 2 ]

[Maximum number: 1]

Hydrogen cyanide, HCN , is a very toxic compound.

(a)

Hydrogen cyanide reacts with hydrogen according to the equilibrium:

\mathrm{HCN}(\mathrm{~g})+2 \mathrm{H}_{2}(\mathrm{~g}) \rightleftharpoons \mathrm{CH}_{3} \mathrm{NH}_{2}(\mathrm{~g})

[ 1 ]

(i)

Determine the oxidation states that indicate that carbon is reduced in this reaction.

Initial oxidation state:
Final oxidation state:

[ 1 ]

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