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A-Level CAIE Chemistry AS1.4 Ionisation energyQuestion Bank

(a)

Define first ionisation energy.

[ 2 ]
(b)

Successive ionisation energies for element A are shown in Table 1.1.

Table 1.1

Table 1.1

Use Table 1.1 to deduce the group of the Periodic Table that A belongs to. Explain your answer. Group

[ 1 ]
(c)

Across Period 3 there is a general trend for first ionisation energies to increase due to the increase in attraction between the nucleus and the outer electron.

Explain why the first ionisation energy of sulfur is less than the first ionisation energy of phosphorus.

[ 2 ]
(d)

In an Al2+\mathrm{A} l^{2+} ion the nuclear attraction for the outer electron is stronger than in an atom of Na .

Compare the electronic structures of Al2+\mathrm{A} l^{2+} and an atom of Na and explain why the third ionisation energy of aluminium is greater than the first ionisation energy of sodium.

[ 2 ]
(a)

The fifth to eighth ionisation energies of three elements in the third period of the Periodic Table are given. The symbols used for reference are not the actual symbols of the elements.

Table
[ 5 ]
(i)

State and explain the group number of element Y.
group number
explanation

[ 1 ]
(ii)

State and explain the general trend in first ionisation energies across the third period.

[ 2 ]
(iii)

Explain why the first ionisation energy of element Y is less than that of element X.

[ 2 ]
(a)

The fifth to eighth ionisation energies of three elements in the third period of the Periodic Table are given. The symbols used for reference are not the actual symbols of the elements.

Table
[ 3 ]
(i)

State and explain the group number of element Y.
group number
explanation

[ 1 ]
(ii)

State and explain the general trend in first ionisation energies across the third period.

[ 2 ]
(a)

The graph shows a sketch of the first ionisation energies of six successive elements in the Periodic Table.

The letters are not the symbols of the elements.

Question image
[ 6 ]
(i)

Explain what is meant by the term first ionisation energy.

[ 3 ]
(ii)

Suggest why the first ionisation energy of B is much less than that of A.

[ 3 ]
(a)
(i)

Explain why the first ionisation energy of sulfur is less than that of phosphorus.

[ 2 ]
[Maximum number: 5]

In the Periodic Table, the p block contains elements whose outer electrons are found in the p subshell.

(a)

Elements in the p block show a general increase in first ionisation energy as the atomic number increases.

[ 5 ]
(i)

Write an equation to show the first ionisation energy of silicon.

[ 1 ]
(ii)

Explain why there is a general increase in first ionisation energies of the elements across Period 3.

[ 2 ]
(iii)

Element A is in the p block.

The graph shows the successive ionisation energies for the removal of the first ten electrons of A.

Question image

State and explain the group of the Periodic Table that element A belongs to. group number
explanation

[ 2 ]
[Maximum number: 3]

Atoms contain the subatomic particles electrons, protons and neutrons. Protons and electrons were discovered by observations of their behaviours in electric fields.

(a)

Electrons in atoms up to 36Kr{ }_{36} \mathrm{Kr} are distributed in s, p and dorbitals.

[ 3 ]
(i)

The first ionisation energies of elements in the first row of the d block (21Sc\left({ }_{21} \mathrm{Sc}\right. to 29Cu)\left.{ }_{29} \mathrm{Cu}\right) are very similar. For all these elements, it is a 4s electron that is lost during the first ionisation.

Suggest why the first ionisation energies of these elements are very similar.

[ 3 ]
[Maximum number: 6]

The graph shows the first ionisation energies of some of the elements in Group 2.

Question image
(a)

Write an equation for the first ionisation energy of Mg .

Include state symbols.

[ 1 ]
(b)

Explain the observed trend in first ionisation energies down Group 2.

[ 3 ]
(c)

The second ionisation energy of Be is 1757 kJ mol−11757 \mathrm{~kJ} \mathrm{~mol}^{-1}.

Explain why the second ionisation energy of Be is higher than the first ionisation energy of Be.

[ 2 ]
[Maximum number: 6]

Fig. 1.1 shows how first ionisation energies vary across Period 2.

Fig. 1.1

Fig. 1.1

(a)

Construct an equation to represent the first ionisation energy of oxygen. Include state symbols.

[ 1 ]
(b)
(i)

State and explain the general trend in first ionisation energies across Period 2.

[ 3 ]
(ii)

Explain why ionisation energy A in Fig. 1.1 does not follow the general trend in first ionisation energies across Period 2.

[ 2 ]
[Maximum number: 1]

The first four ionisation energies for element X are shown in the table.

Table

Which ion of X is produced by removing an electron from a filled shell?

A

X+\mathrm{X}^{+}

B

X2+\mathrm{X}^{2+}

C

X3+\mathrm{X}^{3+}

D

X4+\mathrm{X}^{4+}

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