, Section A: Principles of Chemistry
1 a) electron b) electron
c) proton and neutron d) proton and electron
e) neutron
2 a) metals; non-metals; lost, gained; high; high
b) i) 2.8.2; 2.8.7 ii) 2.8; 2.8.8
3 a) Starting states – B; B; A; C Finishing states – A; C; C; A
b) B
c) element; mixture; mixture; compound
4 a) Atoms that have the same number of protons but different numbers of neutrons.
It is essential to include the word atom in your answer.
Chemistry Revision Guide
Alternative answer
Atoms with same atomic number but different mass numbers, or atoms of the same
element with different masses.
b) i) First row – 37; 48 Second row – 37; 87
(85 ! 71) + (87 ! 28)
ii) = 85.6
100
c) They have the same electronic configuration.
Do not mention protons or neutrons in your answer.
Chemical reactions involve only electrons.
Alternative answer
Both have same number of electrons in the outer shell, or both have one electron in
the outer shell.
d) i) Rb2O; RbCl
ii) Any two from: • rubidium fizzes or bubbles or moves around
• rubidium disappears or dissolves
• rubidium melts or forms a ball
• rubidium catches fire or explodes or flame is produced
iii) 2Rb + 2H2O → 2RbOH + H2
5 a) Electrons within the structure are free to move.
b) Ions cannot move until the lead(II) bromide is a liquid.
1
, c) First reaction – B and reduction
Second reaction – A and oxidation
d) i) Amount of Pb = 0.05 mol; Amount of Br2 = 0.05 mol
ii) Mass of bromine = 0.05 x 160 g = 80 g
6 a) i) (39 + 16 + 1) = 56
14.0
ii) = 0.25 mol
56
1000
iii) 0.25 ! = 1.0 mol/dm 3
250
200
b) i) ! 2.0 = 0.40 mol
1000
1
ii) ! 0.40 = 0.20 mol
2
Chemistry Revision Guide
iii) 0.20 ! 24 = 4.8 dm 3
7 a) Allotropy
Allotropy is no longer on the specification.
b) Covalent. The attraction of each of the two nuclei for a shared pair of electrons.
c) Cutting or drilling.
d)
e) Both are giant structures containing lots of covalent bonds that have to be broken.
It requires a lot of energy to break these bonds.
8 a) The force of attraction between two nuclei and a pair of electrons shared between them.
b) simple; weak; molecules; low.
2
1 a) electron b) electron
c) proton and neutron d) proton and electron
e) neutron
2 a) metals; non-metals; lost, gained; high; high
b) i) 2.8.2; 2.8.7 ii) 2.8; 2.8.8
3 a) Starting states – B; B; A; C Finishing states – A; C; C; A
b) B
c) element; mixture; mixture; compound
4 a) Atoms that have the same number of protons but different numbers of neutrons.
It is essential to include the word atom in your answer.
Chemistry Revision Guide
Alternative answer
Atoms with same atomic number but different mass numbers, or atoms of the same
element with different masses.
b) i) First row – 37; 48 Second row – 37; 87
(85 ! 71) + (87 ! 28)
ii) = 85.6
100
c) They have the same electronic configuration.
Do not mention protons or neutrons in your answer.
Chemical reactions involve only electrons.
Alternative answer
Both have same number of electrons in the outer shell, or both have one electron in
the outer shell.
d) i) Rb2O; RbCl
ii) Any two from: • rubidium fizzes or bubbles or moves around
• rubidium disappears or dissolves
• rubidium melts or forms a ball
• rubidium catches fire or explodes or flame is produced
iii) 2Rb + 2H2O → 2RbOH + H2
5 a) Electrons within the structure are free to move.
b) Ions cannot move until the lead(II) bromide is a liquid.
1
, c) First reaction – B and reduction
Second reaction – A and oxidation
d) i) Amount of Pb = 0.05 mol; Amount of Br2 = 0.05 mol
ii) Mass of bromine = 0.05 x 160 g = 80 g
6 a) i) (39 + 16 + 1) = 56
14.0
ii) = 0.25 mol
56
1000
iii) 0.25 ! = 1.0 mol/dm 3
250
200
b) i) ! 2.0 = 0.40 mol
1000
1
ii) ! 0.40 = 0.20 mol
2
Chemistry Revision Guide
iii) 0.20 ! 24 = 4.8 dm 3
7 a) Allotropy
Allotropy is no longer on the specification.
b) Covalent. The attraction of each of the two nuclei for a shared pair of electrons.
c) Cutting or drilling.
d)
e) Both are giant structures containing lots of covalent bonds that have to be broken.
It requires a lot of energy to break these bonds.
8 a) The force of attraction between two nuclei and a pair of electrons shared between them.
b) simple; weak; molecules; low.
2
