Syllabus Edition

First teaching 2023

First exams 2025

|

Electrons, Energy Levels & Atomic Orbitals (CIE AS Chemistry)

Exam Questions

47 mins16 questions
1a1 mark

Aluminium is a metal in Group 13

Complete the electron configuration in Fig. 3.1 for an aluminium atom using box notation.

1-1-atomic-structure-2c-a
Fig. 3.1
1b1 mark

Draw the orbital of the 2s orbital on the axis in Fig. 3.2.

1-1-3b-e-orbital-axis
Fig. 3.2
1c1 mark

The first ionisation energy values of Li, Mg and Na are shown in Table 3.1

Table 3.1

Element First ionisation energy (kJ mol-1)
  496
Li 520
  738


Complete the table.

1d2 marks

Explain why the first ionisation energy of aluminium is lower than the first ionisation energy of magnesium.

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1a4 marks

The model of the nuclear atom was first proposed by Ernest Rutherford. He developed this model on the basis of results obtained from an experiment using gold metal foil.

Complete the Table 2.1 with information for two of the particles in an atom of 197Au.

Table 2.1
 
Particle Relative mass Relative charge Location within atom Total number in an atom of 197Au
electron 0.0005 -1   79
neutron     nucleus   

1b3 marks

A sample of gold found in the earth consists of only one isotope.

i)
Explain what is meant by the term isotopes
[2]

ii)
A different sample of gold contains more than one isotope.

Suggest why this different sample of gold has the same chemical properties as the sample found in the earth.
[1]
1c1 mark

Gold(III) chloride, traditionally called auric chloride, is one of the most common compounds of gold.

It has the formula AuCl3.

Complete the electron configuration for the chloride ion using box notation.

1-1-atomic-structure-2c-a

1d3 marks

On the axes shown in Fig. 2.1, draw a sketch diagram of one of each different type of orbital that is occupied by the electrons in a Period 3 element. 

Label each type of orbital. 

1-1-atomic-structure-2d-a

Fig. 2.1

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2a1 mark

State the full electron configuration for chromium.

2b2 marks

State the meaning of [Ar] and complete the orbital diagram shown in Fig. 2.1 for chromium.

2-1-ib-chemistry-sq-q3c-medium

Fig. 2.1

2c2 marks

This question is about the chromium(III) ion, Cr presubscript 24 presuperscript 52 superscript 3 plus end superscript.

i)
State the number of protons, electrons, and neutrons in the chromium(III) ion. 
[1]
 
ii)
Write the full electron configuration for the chromium(III) ion. 
[1]

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3a3 marks

Electron configurations give you a summary of where you can find an electron around the nucleus of an atom. They can also be determined for an ion after an atom loses or gains electrons.

i)
State the full electron configuration of the rubidium ion, Rb presubscript 37 presuperscript 85 superscript plus. 
[1]
 
ii)
State and explain the relative size of a rubidium ion compared to a krypton atom. 
[2]

3b2 marks

The electrons in an atom are found in orbitals around the nucleus, which have different energy levels sometimes called shells.

i)
The fourth shell consists of the atomic orbitals 4d, 4f, 4p and 4s. List these orbitals in order of increasing energy. 
[1]
 
ii)
State the number of atomic orbitals present in 4d, 4f, 4p and 4s. 
[1]

 

3c1 mark

Rubidium forms an ionic compound with selenium, Rb2Se Using boxes to represent orbitals and arrows to represent electrons, sketch the orbital diagram of the valence shell of selenium on the axis provided in Fig. 3.1.

2-1-ib-chemistry-sq-q5d-medium

Fig. 3.1

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1a2 marks

In the blast furnace, carbon can react with oxygen to form carbon dioxide and carbon monoxide.

Write one equation for the this reaction. 

1b2 marks

Identify and draw the subshell on Fig. 5.2 which has the highest occupied energy level in an oxygen atom.

 
Subshell …………………………….
 
[1]
 
Diagram
1-1-3b-e-orbital-axis
Fig. 5.2

[1]

1c5 marks
i)
Complete Fig. 5.2 to show the excited state of a carbon atom.
 
1-1-atomic-structure-2c-a
 
Fig. 5.2 
 
[1]
 
ii)
Identify the type of hybridisation that arises in a molecule of carbon monoxide for both atoms and explain how this hybridisation occurs

Hybridisation ………….

Explanation
[4]

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