1 Hydrogen reacts much more readily with alkenes than with alkanes.
Why is this?
A Alkenes are polar molecules whereas alkanes are not.
B All atoms in an alkane have a full outer shell of electrons.
C The bond enthalpy of C–C σ bonds is higher than that of π bonds.
D The bond enthalpy of C–C σ bonds is lower than that of π bonds.
Your answer [1]
2 The structure of a hydrocarbon is shown below.
Which terms describe this hydrocarbon?
A Alicyclic and saturated
B Aliphatic and alicyclic
C Aliphatic and aromatic
D Aromatic and unsaturated
Your answer [1]
© OCR 2025. You may photocopy this page. 1 of 31 Created in ExamBuilder
, 3 Which diagram shows a p-orbital?
A
B
C
D
Your answer [1]
4 This question is about transition elements.
Iron is in the d block of the periodic table and contains s, p and d orbitals.
• Draw diagrams to show the shapes of an s orbital and a p orbital.
• Complete the electron configurations of an iron atom and an iron(II) ion.
Shapes
s orbital p orbital
Electron configurations
Iron atom: 1s2
Iron(II) ion 1s2 [2]
© OCR 2025. You may photocopy this page. 2 of 31 Created in ExamBuilder
, 5 Chlorine has the electron configuration [Ne]3s23p5.
Which statement(s) about chlorine is/are correct when it reacts in redox reactions?
1 It can gain one electron to form 1– ions.
2 It can lose its 3s2 electrons to form 2+ ions.
3 It can lose its 3p5 electrons to form 5+ ions.
A 1, 2 and 3
B Only 1 and 2
C Only 2 and 3
D Only 1
Your answer [1]
6 Oxygen has the electron configuration 1s22s22p4.
How are the electrons in an atom of oxygen arranged in the p-orbitals?
A
B
C
D
Your answer [1]
© OCR 2025. You may photocopy this page. 3 of 31 Created in ExamBuilder
, 7(a) Hydrogen and oxygen have different electronegativities.
What is meant by the term electronegativity?
[2]
(b) H2O is a polar molecule that has hydrogen bonding.
i. Complete the diagram below to show hydrogen bonding between the H2O molecule shown and another H2O
molecule.
Include relevant dipoles and lone pairs.
Label the hydrogen bond.
[2]
ii. Explain why molecules of H2O are polar.
[1]
iii. One unusual property of H2O is that ice floats on water.
Explain why ice has a lower density than water.
[1]
© OCR 2025. You may photocopy this page. 4 of 31 Created in ExamBuilder
Why is this?
A Alkenes are polar molecules whereas alkanes are not.
B All atoms in an alkane have a full outer shell of electrons.
C The bond enthalpy of C–C σ bonds is higher than that of π bonds.
D The bond enthalpy of C–C σ bonds is lower than that of π bonds.
Your answer [1]
2 The structure of a hydrocarbon is shown below.
Which terms describe this hydrocarbon?
A Alicyclic and saturated
B Aliphatic and alicyclic
C Aliphatic and aromatic
D Aromatic and unsaturated
Your answer [1]
© OCR 2025. You may photocopy this page. 1 of 31 Created in ExamBuilder
, 3 Which diagram shows a p-orbital?
A
B
C
D
Your answer [1]
4 This question is about transition elements.
Iron is in the d block of the periodic table and contains s, p and d orbitals.
• Draw diagrams to show the shapes of an s orbital and a p orbital.
• Complete the electron configurations of an iron atom and an iron(II) ion.
Shapes
s orbital p orbital
Electron configurations
Iron atom: 1s2
Iron(II) ion 1s2 [2]
© OCR 2025. You may photocopy this page. 2 of 31 Created in ExamBuilder
, 5 Chlorine has the electron configuration [Ne]3s23p5.
Which statement(s) about chlorine is/are correct when it reacts in redox reactions?
1 It can gain one electron to form 1– ions.
2 It can lose its 3s2 electrons to form 2+ ions.
3 It can lose its 3p5 electrons to form 5+ ions.
A 1, 2 and 3
B Only 1 and 2
C Only 2 and 3
D Only 1
Your answer [1]
6 Oxygen has the electron configuration 1s22s22p4.
How are the electrons in an atom of oxygen arranged in the p-orbitals?
A
B
C
D
Your answer [1]
© OCR 2025. You may photocopy this page. 3 of 31 Created in ExamBuilder
, 7(a) Hydrogen and oxygen have different electronegativities.
What is meant by the term electronegativity?
[2]
(b) H2O is a polar molecule that has hydrogen bonding.
i. Complete the diagram below to show hydrogen bonding between the H2O molecule shown and another H2O
molecule.
Include relevant dipoles and lone pairs.
Label the hydrogen bond.
[2]
ii. Explain why molecules of H2O are polar.
[1]
iii. One unusual property of H2O is that ice floats on water.
Explain why ice has a lower density than water.
[1]
© OCR 2025. You may photocopy this page. 4 of 31 Created in ExamBuilder
