Edexcel A-Level Chemistry Paper 1, June 2023: Question 2

5 marks · Easy difficulty · Short Open Response

State the meaning of an orbital, draw the shapes of s and p orbitals, and identify the electronic configuration of a copper atom.

Practise this question

Question

Question text

2 Chemists often use the term ‘orbital’ when considering atomic structure.

(a) State what is meant by the term orbital.

(2)

(b) Draw diagrams to show the shape of an s and a p orbital.

(2)

s orbital p orbital

(1)

A [Ar]4s13d10

B [Ar]4s23d9

C [Ar]4s24p13d8

D [Ar]4s24p23d7

(Total for Question 2 = 5 marks)

Mark scheme

Show the mark scheme

Question

Answer Additional Guidance Mark

Number

2(a) An answer that makes reference to the following points: Mark independently (2)

Allow area / for region / space

• a region / space (in an atom) in which there is a high probability of Allow a percentage between 90 and 98% for the

finding electron(s) / electron(s) are (most) likely to be found (1) probability

Allow just ‘a region / space (in an atom) that

holds electrons’

Allow an area of high electron density where an

electron can be predicted to be found

Allow region / space around the nucleus that

holds electrons

Ignore just ‘where the electron(s) are’

Ignore energy level / sub-level

• containing (a maximum of ) 2 / a pair of electrons (with opposite

spin) (1)

Question

Answer Additional Guidance Mark

Number

2(b) An answer that makes reference to the following points: s orbital p orbital (2)

• s orbital shown as a sphere / circle (1)

• p orbital shown as a figure of 8 / dumb-bell shaped (1)

Allow p orbital in any orientation

Lower p orbital does not need to be shaded

Allow all 3 p orbitals shown separately or altogether

Ignore x, y and/or z axes marked

Do not award p-orbital lobes of very different sizes

Note Do not award 2 p orbitals shown as a clover shape

unless labelled as separate orbitals (px etc)

Question

Answer Mark

Number

2(c) The only correct answer is A ([Ar]4s13d10) (1)

B is not correct because a full d-subshell is more stable

C is not correct because the atom does not have any 4p electrons

D is not correct because the atom does not have any 4p electrons

(Total for Question 2 = 5 marks)

How to answer it

Atomic Structure and Electron Orbitals

What this question tests

This question assesses your fundamental understanding of quantum atomic models, specifically the definition of an atomic orbital, the spatial shapes of s and p orbitals, and the rules governing electron configurations of transition metals (including the stability of fully filled d-subshells).

Question 2(a)

Definition of an Orbital

✅ Correct Answer

1. A region or space in an atom in which there is a high probability of finding electrons.
2. Containing a maximum of 2 electrons (with opposite spin).

Awarded as 2 independent marking points (1 mark each).

💡 Key Knowledge

An orbital is a wave function solution to the Schrödinger wave equation. It describes the volume of space where an electron is likely to be found (usually defined as a 95% or 90-98% probability surface).

❌ Common Errors

Confusing an orbital with an energy level or sub-level.
Stating it is the exact path or orbit of an electron (like planets around the sun), which violates Heisenberg's Uncertainty Principle.
Failing to mention the maximum electron capacity (2 electrons).

🧠 Exam Technique

Memorise the precise definition. Examiners strictly look for two components: probability of finding electrons and maximum capacity of 2 electrons.

Question 2(b)

Shapes of s and p Orbitals

✅ Correct Answer

s orbital: A sphere or circle.
p orbital: A figure of 8 or dumb-bell shape.

Total: 2 marks (1 mark per correct drawing).

💡 Key Knowledge

s orbitals are spherically symmetrical around the nucleus. p orbitals consist of two lobes with a node (region of zero electron probability) at the nucleus.

❌ Common Errors

Drawing p-orbitals with lobes of drastically different sizes.
Drawing a clover-leaf shape for a p orbital (which is actually a d orbital).
Failing to draw a clear, closed spherical outline for the s orbital.

🧠 Exam Technique

Keep sketches simple and clear. For the p orbital, draw a clean figure-of-eight (dumb-bell). Shading is not required, and any orientation is accepted as long as the shape is recognizable.

Question 2(c)

Electronic Configuration of Copper

✅ Correct Answer

A: [Ar]4s 1 3d 10

Total: 1 mark.

💡 Key Knowledge

Copper (atomic number 29) is an electronic configuration anomaly. Instead of the expected [Ar]4s 2 3d 9 , an electron promotes from the 4s orbital to the 3d orbital to achieve a fully-filled, stable 3d subshell ( 3d 10 ).

❌ Common Errors

Selecting option B out of habit following standard Aufbau filling rules.
Selecting options C or D which mistakenly include non-existent 4p electrons for a ground-state copper atom.

🧠 Exam Technique

Learn the two major d-block configuration exceptions: Chromium (Cr) ( 4s 1 3d 5 ) and Copper (Cu) ( 4s 1 3d 10 ). Examiners frequently test these anomalies.

Topics

Physical Chemistry · Topic 1: Atomic Structure and the Periodic Table

Question and mark scheme from the Edexcel A-Level Chemistry examination, Paper 1, June 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.