Edexcel A-Level Chemistry Paper 1, June 2023: Question 1
2 marks · Medium difficulty · Short Open Response
Identify a d-block element in Period 4 from a graph of ionisation energy against atomic number and state the meaning of the term d-block element.
Practise this questionQuestion
Question text
1 This question is about d‑block elements.
(a) Which of the labels 1–4 identifies a d‑block element in Period 4?
Ionisation
energy
10 20 30 40 50 60
Atomic number
(1)
A 1
B 2
C 3
D 4
(b) State what is meant by the term d‑block element.
(1)
(Total for Question 1 = 2 marks)
Mark scheme
Show the mark scheme
Question
Answer Mark
Number
1(a) The only correct answer is B (2) (1)
A is not correct because it is an s-block element
C is not correct because it is a p-block element
D is not correct because it is a d-block element in Period 5
Question
Answer Additional Guidance Mark
Number
1(b) An answer that makes reference to the following point: Allow ‘d orbital(s)’ for ‘d-subshell’ throughout (1)
Do not award ‘d block orbital’
• an element which has its last electron added to a d-subshell Allow an element with its valence / outer /
(according to the Aufbau principle) outermost / last / highest energy electron in
the d-subshell
Allow outer occupied orbital is d
Allow electronic configuration ends with d-subshell
Allow 3d specified
Ignore just ‘outer orbital is d’
Ignore reference to forming stable ions with
incomplete d orbitals
Ignore general properties of transition metals e.g. has
variable oxidation states
Do not award just ‘ has electron(s) in d orbitals /
d-subshell’
(Total for Question 1 = 2 marks)
How to answer it
Properties and Identification of d-block Elements
This question assesses your ability to interpret periodic trends across a long-form successive ionisation energy graph up to atomic number ~55, recognise block regions of the periodic table, and accurately recall precise chemical definitions for atomic subshell classifications.
Identifying a Period 4 d-block Element
✅ Correct Answer
B (Label 2)
Label 2 points to the section of Period 4 after the s-block elements (atomic numbers 19 and 20, potassium and calcium) where electrons begin filling the 3d subshell (Scandium onwards, atomic numbers 21–30).
💡 Key Knowledge
- Period 4 spans atomic numbers 19 to 36.
- Elements 19 (K) and 20 (Ca) are s-block (labelled by 1).
- Elements 21 to 30 (Sc to Zn) are the Period 4 d-block elements.
- Elements 31 to 36 (Ga to Kr) are p-block elements (labelled by 3).
❌ Common Errors & Distractor Analysis
- A (Label 1): Points to s-block elements in Period 4.
- C (Label 3): Points to p-block elements in Period 4.
- D (Label 4): Points to a d-block element, but it is located in Period 5 (atomic numbers 39–48), not Period 4. Always cross-reference the atomic number axis!
Defining a d-block Element
✅ Correct Answer
An element which has its last electron added to a d-subshell (according to the Aufbau principle).
🧠 Exam Technique & Wording
Examiners are very strict with definitions. You must specify that the electron enters the d-subshell (or d-orbital).
Allowed variations: Referring to the valence/outer/highest energy electron entering the d-subshell, or stating that the electronic configuration ends with a d-subshell.
❌ Common Errors
- Saying simply that the element "has electrons in d-orbitals" (this is insufficient because many transition metal ions or subsequent elements have filled/partially filled d-orbitals; the definition relies on subshell filling order).
- Writing "d-block orbital" (incorrect terminology—use d-subshell or d-orbital).
- Describing general transition metal properties like variable oxidation states or colored ions, which do not answer the specific question asked about the d-block definition.
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.