Monday 15 June 2026 – Morning
A Level Chemistry A
H432/03 Unified chemistry
Time allowed: 1 hour 30 minutes
You must have:
*
• the Data Sheet for Chemistry A
You can use:
• a scientific or graphical calculator
• an HB pencil
* H 4 3 2 0 3 *
*
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 70.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 20 pages.
ADVICE
• Read each question carefully before you start your answer.
Cambridge OCR 2026 [601/5255/2] Cambridge OCR is an exempt Charity
DC (ST/SG) 362811/7 Turn over
, 2
1 This question is about the first 36 elements in the periodic table, and their compounds. The first
36 elements are shown in Figure 1.1.
Figure 1.1
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
(a) Chemists used to order elements in the periodic table by increasing atomic mass, but this
method has changed over time.
Identify two pairs of elements in Figure 1.1 that do not fit into ordering the elements by
increasing atomic mass, and explain how these elements are now arranged.
Pair 1 ................... and ................... Pair 2 ................... and ...................
Explanation: .....................................................................................................................................
..........................................................................................................................................................
[2]
(b) State two elements from the first 3 periods (H Ar) in Figure 1.1 that have a giant covalent
lattice structure.
.......................... and .......................... [1]
Which element in Figure 1.1 has the smallest first ionisation energy?
.......................... [1]
(d) State the three elements from Period 4 (K Kr) that have atoms where only three electrons
are unpaired.
.......................... and .......................... and .......................... [2]
Cambridge OCR 2026
, 3
(e) Element M is a transition element in Figure 1.1.
1.20 g of element M reacts with O2 to form 1.80 g of M2O3.
Determine by calculation the identity of element M.
Element M: ......................................................... [3]
(f) The table shows boiling points of hydrides of elements from Figure 1.1.
Boiling point Boiling point
Hydride Hydride
/K /K
Period 2 CH4 112 NH3 240
Period 3 SiH4 161 PH3 185
Explain the following.
• The boiling point of SiH4 is higher than the boiling point of CH4.
• The boiling point of NH3 is higher than the boiling point of PH3.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..................................................................................................................................................... [4]
Cambridge OCR 2026 Turn over
A Level Chemistry A
H432/03 Unified chemistry
Time allowed: 1 hour 30 minutes
You must have:
*
• the Data Sheet for Chemistry A
You can use:
• a scientific or graphical calculator
• an HB pencil
* H 4 3 2 0 3 *
*
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 70.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 20 pages.
ADVICE
• Read each question carefully before you start your answer.
Cambridge OCR 2026 [601/5255/2] Cambridge OCR is an exempt Charity
DC (ST/SG) 362811/7 Turn over
, 2
1 This question is about the first 36 elements in the periodic table, and their compounds. The first
36 elements are shown in Figure 1.1.
Figure 1.1
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
(a) Chemists used to order elements in the periodic table by increasing atomic mass, but this
method has changed over time.
Identify two pairs of elements in Figure 1.1 that do not fit into ordering the elements by
increasing atomic mass, and explain how these elements are now arranged.
Pair 1 ................... and ................... Pair 2 ................... and ...................
Explanation: .....................................................................................................................................
..........................................................................................................................................................
[2]
(b) State two elements from the first 3 periods (H Ar) in Figure 1.1 that have a giant covalent
lattice structure.
.......................... and .......................... [1]
Which element in Figure 1.1 has the smallest first ionisation energy?
.......................... [1]
(d) State the three elements from Period 4 (K Kr) that have atoms where only three electrons
are unpaired.
.......................... and .......................... and .......................... [2]
Cambridge OCR 2026
, 3
(e) Element M is a transition element in Figure 1.1.
1.20 g of element M reacts with O2 to form 1.80 g of M2O3.
Determine by calculation the identity of element M.
Element M: ......................................................... [3]
(f) The table shows boiling points of hydrides of elements from Figure 1.1.
Boiling point Boiling point
Hydride Hydride
/K /K
Period 2 CH4 112 NH3 240
Period 3 SiH4 161 PH3 185
Explain the following.
• The boiling point of SiH4 is higher than the boiling point of CH4.
• The boiling point of NH3 is higher than the boiling point of PH3.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..................................................................................................................................................... [4]
Cambridge OCR 2026 Turn over
