Syllabus Edition

First teaching 2023

First exams 2025

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Ionisation Energy (CIE AS Chemistry)

Exam Questions

1 hour22 questions
1a1 mark

An isotope of element X has two more protons and two more neutrons than an atom of 41K. Use the Periodic Table to identify element X.

1b3 marks

Give the full electronic configuration of the following species:

 
K+ .........................................................................................
 
Ti ..........................................................................................
 
Co ........................................................................................
1c3 marks

Ionisation energy reactions are endothermic processes.

i)
Write the equations for the first ionisation energy of K and the second ionisation energy of Sc
[2]
 
ii)
Give the full electronic configuration of the Sc2+ 
[1]
1d5 marks

Table 2.1 shows successive ionisation energies of element Z in Period 3. 

Table 2.1

  1 2 3 4 5

Ionisation energy
(kJ mol-1)

786 1576 3232 4356 16091

i)
State why the first ionisation energy generally increases from left to right across the Periodic Table. 
[2]
ii)
Using the data of successive ionisation energies in table 2.1, state which group of the Periodic Table element Z belongs to. 

Group .........................

Explanation .........................................................................................................
[3]

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2a2 marks

Give the electron configuration of the following species:


Mg .................................................................

Mg2+ .................................................................
2b2 marks

Write an equation including state symbols to show the first ionisation energy of Mg.

2c2 marks

Explain why the second ionisation energy of Mg is higher that the first ionisation energy.

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1a2 marks

The composition of atoms and ions can be determined from knowledge of atomic number, nucleon number and charge.

Complete Table 1.1.

Table 1.1 

Atomic number Nucleon number Number of electrons Number of protons Number of neutrons Symbol 
9   10     straight F presubscript 9 presuperscript 19 superscript minus
    23 26 32  

1b2 marks

Lithium and potassium are Group 1 metals. 

State the following for the potassium 1+ ion with a nucleon number of 39.

Symbol .......................................

[1] 

Full electronic configuration .................................................

[1] 
1c3 marks

Beams of protons, neutrons and electrons behave differently in an electric field due to their differing properties.


Fig. 1.1 shows the path of a beam of electrons in an electric field.


Add and label lines to Fig. 1.1 to represent the paths of beams of protons and neutrons in the same field.

screen-shot-2023-01-09-at-12-07-30
Fig. 1.1 
1d6 marks

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.

  Ionisation energies, kJ mol-1
  fifth sixth seventh eighth
X 6274 21 269 25 398 29 855
Y 7012 8496 27 107 31 671
Z 6542 9362 11 018 33 606

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]
 
iv)
Complete the electronic configuration of element Z.
1s2 .................
[1]

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2a3 marks

All elements have a value for a first ionisation energy. 

i)
Define the term first ionisation energy of an element.
[2]
ii)
Write the equation for the first ionisation energy of aluminium.
[1]
2b2 marks

Table 3.1 shows successive ionisation energies of an element A, found in period 3 of the Periodic Table.

Table 3.1

Number of electrons 1 2 3 4 5 6 7 8

Ionisation energy (kJ mol-1)

1012 1904 2914 4964 6274 21 268 25 431 29 872

Identify element A. Explain your answer using data from Table 3.1.

2c6 marks

Fig. 3.1 shows the trend in ionisation energy for Period 3 of the Periodic Table.

period-3-ionisation-energies

Fig. 3.1

i) 
Explain why the first ionisation energy increases across Period 3.
[3]
ii)
Explain the deviations in the trend. 
[3]
2d1 mark

Explain why the second ionisation energy of aluminium is a larger value than the first ionisation energy.

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3a2 marks

The first six ionisation energies of an element X are given below in Table 5.1.

Table 5.1

  First Second Third Fourth Fifth Sixth

Ionisation energy 

(kJ mol-1)

950  1800 2700 4800 6000 12 300

Write an equation, with state symbols, for the second ionisation energy of element X.

3b3 marks

Use the data given above to deduce in which group of the Periodic Table element X is placed. Explain your answer.

Group ........................................................

Explanation ............................................................ 

3c4 marks

The first ionisation energies (I.E.) for the elements of Group 4 are given below in Table 5.2.

Table 5.2

Element  C Si Ge Sn Pb
1st I.E (kJ mol-1) 1090 786 762 707 716

Explain the trend shown by these values in terms of the atomic structure of the elements.

3d1 mark

Write the full electronic configuration for germanium.

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1a5 marks

Fig. 1.1 shows the elements from the first three periods of the Periodic Table.

first-three-periods-of-pt

Fig. 1.1

Identify an element that fits each of the following descriptions:

i)
An element that forms a 2- ion with the same electronic configuration as Ne 
[1]
ii)
The Period 3 element with the highest boiling point 
[1]
iii)
The element from the first three periods with the largest atomic radius 
[1]
iv)
The element from the first three periods with the highest first ionisation energy
[1]
v)
The Period 3 element with the successive ionisation energies shown in Table 1.1

Table 1.1 

Ionisation number

1st

2nd

3rd

4th

Ionisation energy / kJ mol−1

738

1451

7733

10541

[1]
1b5 marks

Fig. 1.2 shows the first ionisation energies for six consecutive elements labelled A-F. 

ionisation-energy-graph-

Fig. 1.2 

Complete the graph to show the first ionisation energies of elements G-K.

1c2 marks

Explain why the value of the first ionisation energy for D is greater than for C.

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2a4 marks

Successive ionisation energies provide evidence for the arrangement of electrons in atoms. In Table 2.1, the successive ionisation energies of oxygen are given.

Table 2.1

Ionisation number 1 2 3 4 5 6 7 8
Ionisation energy / kJ mol-1 1314 3388 5301 7469 10989 13327 71337 84080

 

i)
Give the equation, including state symbols, for the third ionisation energy of oxygen. 
 
[2]

ii)
Explain how this data shows evidence of two energy shells in oxygen.
 
[2]

2b3 marks

Give the full electron configuration of the following atoms and ions.

 
i)
Te
 
[1]
 
ii)
Zn2+
 
[1]
 
iii)
Cu2+
 
[1]
2c
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2 marks

Palladium is a transition metal that is primarily used in a catalytic converter.

 
i)
Give the electron configuration for the Zirconium 2+ ion, Zr2+, starting with [Kr]. 
 
[1]
 
ii)
Give the equation including state symbols to represent the third ionisation energy of Zirconium, Zr.
 
[1]

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