1. C2 Foundation Smart teach sessions 1 and 2
This covers three topics in two lessons. Spread it out over the two lessons however you wish. But do not let the pace go. There are 6 topics in C2 and only four lesson to teach it all.

2. Structure of an atom. ELECTRON – negative, mass nearly nothing
PROTON – positive, same mass as neutron (“1”)
NEUTRON – neutral, same mass as proton (“1”)
Students must know locations, charges and masses of the three parts.

3. Exam Q1.
(a) The diagram shows an atom of lithium.
(i) A proton has been labelled.
Complete the diagram by labelling the other two particles shown.
(2)

4. D proton positive, electron negative (1)
(b) (i) Which row of the table shows the charge on a proton and the charge on an electron?
(1)
proton
electron
   A
positive
   B
negative
   C
   D
(b)(i)
D proton positive, electron negative
(1)

5. Electron structure 39 K 19 Consider an atom of Potassium:
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Consider an atom of Potassium:
Nucleus K 19 39
Potassium has 19 electrons. These electrons occupy specific energy levels “shells”…
Pupils must know the electronic structure of an atom. The inner shell is filled first then the second and then the third and so on.
The inner shell has __ electrons
The next shell has __ electrons
The next shell has the remaining __ electron
Electron structure
= 2,8,8,1

6. Electron structure 14 24 40 N Mg Ca 7 12 20 Electron structure = 2,5
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Draw the electronic structure of the following atoms: 14 24 40 N Mg Ca 7 12 20
Nucleus
Nucleus
Nucleus
A bit of practice on the structure
Electron structure
= 2,5
Electron structure
= 2,8,2
Electron structure
= 2,8,8,2

7. An atom of phosphorus contains 15 electrons.
Describe how these 15 electrons are arranged in a phosphorus atom.
(2)
Answer
Acceptable answers
Mark
A description to include · 2.8 (in 1st and 2nd shell)(1) · 5 (in outer shell)(1)
suitable diagram in place of 2.8(1).5(1) electrons in shells / orbits / rings(1)
(2)

8. Mass and atomic number 4 He 2 10/11/2018 10/11/2018 Particle
Relative Mass
Relative Charge
Proton 1 +1
Neutron
Electron
Very small -1
MASS NUMBER = number of protons + number of neutrons He 2 4
Pupils must know the table as it will not be given to them – favourite question to ask to fill it in.
Mass number is always the biggest number in the box. (not always on the top) They will get a periodic table with the symbol key on it.
There is no overall charge on an atom as the electrons equal the protons – needed for later.
SYMBOL
PROTON NUMBER = number of protons (obviously)

9. Q3.
(a) Complete the table to show the relative mass of a neutron and of an electron.
(2)

10. Q2.
(a) Complete the sentence by putting a cross ( ) in the box next to your answer.
The particles in atoms are electrons, neutrons and protons.
The mass of an electron is
(1)
A greater than the mass of a neutron
B the same as the mass of a proton
C smaller than the mass of a proton
D the same as the mass of a neutron
Answer
Acceptable answers
Mark
(a)
C smaller than the mass of a proton
(1)

11. Atomic mass in more detail
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RELATIVE ATOMIC MASS, Ar (“Mass number”) = number of protons + number of neutrons He 2 4
SYMBOL
PROTON NUMBER = number of protons (obviously) – this number is always the same for an element

12. (b) The atomic number of oxygen is 8.
The mass number of an atom of oxygen is 17.
Describe the number and type of particles in the nucleus of this atom.
(2)
(b)
An description linking · 8 protons (1) · (and) 17-8/9 neutrons (1)
ignore references to electrons in shells / charges on particles if electrons in nucleus max 1 protons and neutrons with incorrect numbers (1)
(2)

13. The Periodic Table
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Fact 1: Elements in the same group have the same number of electrons in the outer shell (this corresponds to their group number) H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Fe Ni Cu Zn Br Kr Ag I Xe Pt Au Hg
These elements have __ electrons in their outer shells
Group number tells you how many electrons in the outer shell.
Period number tells you how many shells there are in the atom.
These elements have __ electrons in their outer shell
E.g. all group 1 metals have __ electron in their outer shell

14. The electronic configuration of lithium is 2.1.
The electronic configuration of sodium is
(i) Explain, in terms of their electronic configurations, why lithium and sodium are both in group 1 of the periodic table.
(2)
(ii) Explain, in terms of their electronic configurations, why lithium is placed in period 2 and sodium is placed in period 3
of the periodic table.

15. (c)(i)
An explanation linking · (both have) one electron (1) · in the outer shell/orbit/energy level (1)do not award first mark if proton/neutron/atom (in outer shell)
both have one outer electron (2) both need to lose 1 electron to have a full outer shell (2) fully correct diagrams of lithium and sodium showing electronic configurations (1) have the same number of electrons in the outer shell (1)
(c)(ii)
An explanation linking · lithium has 2 shells/orbits/energy levels (1) · sodium has 3 shells/orbits/energy levels (1) max 1 mark if outer/full shells max 1 mark if rings/circles/layers
If no marks awarded from 'answer' column, allow any one from sodium is more reactive than lithium ORA (1) sodium has more electrons than lithium ORA (1) sodium has more shells than lithium ORA (1) ignore reactivity increases down the group

16. (b) Complete the sentence by putting a cross ( ) in the box next to your answer.
An atom has no overall charge because it contains
(1)
A more protons than electrons
B the same number of electrons and protons
C the same number of electrons and neutrons
D more neutrons than electrons
(c) The atomic number of lithium is 3.
The mass number of an atom of lithium is 7.
State the name and number of each of the particles in the nucleus of this atom.
(2)

18. Q9.
* An atom of beryllium has an atomic number of 4 and a mass number of 9.
Describe the numbers and arrangements of the protons, neutrons and electrons in this atom.
(6)

19. Question Number
Indicative content
Mark
QWC *
A description including some of the following points •   four protons •   five neutrons •   four electrons •   protons in nucleus •   neutrons in nucleus •   electrons in shells •   two electrons in first shell •   two electrons in second/outer shell last two points could be expressed as electronic configuration is 2.2 allow correct diagram
(6)
Level
no rewardable material 1
1-2
•   correct number or position of one type of particle / correct numbers or positions or two particles •   the answer communicates ideas using simple language and uses limited scientific terminology •   spelling, punctuation and grammar are used with limited accuracy 2
3-4
•   correct number and position of one type of particle and two other correct numbers and /or positions of other particle(s) •   the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately •   spelling, punctuation and grammar are used with some accuracy 3
5 - 6
•   correct number and position of all three particles / one error in former and correct electronic configuration •   the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately •   spelling, punctuation and grammar are used with few errors

20. Flame tests
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A flame test - clean wire with (hydrochloric) acid, put wire into solid then hold wire in flame. observe the colours produced:
Lithium
Red
Sodium
Yellow
Potassium
Lilac
Calcium
Orange-red
Barium
Green
Flame test procedure comes up every no and then, but always a question on the colour of one of these metals.

21. The colour produced in a flame test by calcium ions is (1) A green
Q1.
(i) Complete the sentence by putting a cross ( ) in the box next to your answer.
The colour produced in a flame test by calcium ions is
(1)
A green
B lilac
C orange-red
D yellow
(ii) Describe how a flame test is carried out on a solid.
(2)
Answer
Acceptable answers
Mark
(i)
C orange-red
(1)
(ii)
A description including two points from CLEAN · clean (flame test) wire with (hydrochloric) acid (1) SAMPLE · put (wire) into solid (1)TEST · hold (wire) in (Bunsen) flame (1)
· moisten splint · put splint into solid · hold splint in (Bunsen) flameignore : hold over flame use of tongs / spatula etc for equipment, max 1  
(2)

22. Solubility rules
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The following guidelines are useful in working out if a substance will dissolve:
All common sodium, potassium and ammonium salts are soluble
All nitrates are soluble
Common chlorides are soluble but not silver and lead
Common sulfates are soluble but not those of lead, barium and calcium
Common carbonates and hydroxides are insoluble except those of sodium, potassium and ammonium

23. Precipitation Reactions
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A precipitation reaction occurs when an insoluble solid is made by mixing two ionic solutions together.
Method:
1) Mix the reactants together
2) Filter off the precipitate
Comes up many times. Very simple version Mix, filter, wash, dry – easy marks
3) Wash the residue
4) Dry the residue in an oven at 50OC

24. Q2.
* Barium sulfate is prepared by reacting barium chloride with sodium sulfate.
The barium sulfate is formed as a precipitate.
Describe an experiment to prepare a pure, dry sample of barium sulfate, starting with barium chloride crystals and sodium sulfate crystals.
(6)

25. Indicative Content
Mark
QWC *
A description including some of the following points reactants · dissolve reactants (in water) · mix reactants / solutions · use of appropriate apparatus · stir separate product · filter · use of filter funnel and papermaking pure dry salt · solid on filter paper · wash with water · dry in oven / leave to dry / in a warm place
(6)
Level
No rewardable content 1
1 - 2
· a limited description e.g. mix the two reactants in a beaker OR wash solid and leave to dry. · the answer communicates ideas using simple language and uses limited scientific terminology · spelling, punctuation and grammar are used with limited accuracy 2
3 - 4
· a simple description e.g. mix solutions of the reactants in a beaker and then filter. · the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately · spelling, punctuation and grammar are used with some accuracy 3
5 - 6
· a detailed description e.g. mix solutions of the reactants in a beaker then filter, wash solid and leave to dry. · the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately · spelling, punctuation and grammar are used with few errors

26. Barium Sulfate
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Barium sulfate can be used as part of a “barium meal” to X-ray patients. Why?
Barium sulfate is opaque to X rays so they will show up in an X ray
It’s insoluble so it won’t pass into the bloodstream
Use of a precipitate – Barum Sulfate is the only one that comes up regularly (other than testing for carbon dioxide)
Two points for it use are needed.

27. Many barium salts are toxic. Barium sulfate is insoluble in water.
Q3.
This is an X-ray photograph of part of a patient's body. Before the photograph was taken a suspension of barium sulfate was introduced into his body to show the required part.
Many barium salts are toxic. Barium sulfate is insoluble in water.
Explain why it is safe for the patient to have barium sulfate in his body.
(2)
Answer
Acceptable answers
Mark
An explanation linking two of the following points: · barium sulfate does not dissolve (in water) (1) · is not absorbed into blood / body (1) · passes through body (unchanged) (1)
  ignore barium sulfate is insoluble in water mix with / enter blood allow 'barium sulfate does not dissolve into the bloodstream' for 2 marks allow 'it is insoluble so it is nontoxic' for one mark
(2)

28. Introduction to Bonding Revision
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Hi. My name’s Johnny Chlorine. I’m in Group 7, so I have 7 electrons in my outer shell Cl
I’d quite like to have a full outer shell. To do this I need to GAIN an electron. Who can help me?

29. Covalent Bonding
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Here comes another one of my friends, Harry Hydrogen
Hey Johnny. I’ve only got one electron but it’s really close to my nucleus so I don’t want to lose it. Fancy sharing? H Cl H
Now we’re both really stable. We’ve formed a covalent bond.

30. Covalent bonding Consider an atom of hydrogen:
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Consider an atom of hydrogen:
Notice that hydrogen has just __ electron in its outer shell. A full (inner) shell would have __ electrons, so two hydrogen atoms get together and “_____” their electrons:
Now they both have a ____ outer shell and are more _____. The formula for this molecule is H2.
When two or more atoms bond by sharing electrons we call it ____________ BONDING. This type of bonding normally occurs between _______ atoms. It causes the atoms in a molecule to be held together very strongly but there are ____ forces between individual molecules. This is why covalently-bonded molecules have low melting and boiling points (i.e. they are usually ____ or ______).
Words – gas, covalent, non-metal, 1, 2, liquid, share, full, weak, stable
Answers 1,2,share,full, stable,covalent,non-metal,weak,liquid,gas

31. (a) The diagram shows the structure of diamond.
(i) Describe what each represents.
(2)
(ii) State the type of bonding in the diamond structure.
(1)

33. (c) Sulfur and oxygen are both in group 6 of the periodic table.
Explain, in terms of their electronic configurations, why they are both in group 6.
(2)
(d) An atom of phosphorus contains 15 electrons.
Describe how these 15 electrons are arranged in a phosphorus atom.
(e) Phosphorus oxide is a compound that contains covalent bonds.
(i) Describe what is meant by a covalent bond.

34. (c)
Explanation linking · (both have) same number (of electrons) in outer shell(1) · 6 (electrons in outer shell) (consequent on first point) (1)
correct electronic configurations or diagrams alone max 1 'they both have 6 in the outer shell' scores both marks allow 'both need 2 (more) (electrons) to fill outer shell' for both marks
(2)
(d)
A description to include · 2.8 (in 1st and 2nd shell)(1) · 5 (in outer shell)(1)
suitable diagram in place of 2.8(1).5(1) electrons in shells / orbits / rings(1)
(e)(i)
A description to include · electron(s) shared (1) · pair(s) of / two (electrons) (1)
can be shown in a diagram of a covalent bond any mention of ions scores zero

35. Chromatography
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Chromatography can be used to separate a mixture of different inks. Some example questions…
R G B X Z
1) Ink X contains two different colours. What are they?
2) Which ink is ink Z made out of?

36. Rf value
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The Rf value is a way of measuring how far a substance has moved:
This line marks the distance travelled by the solvent
R G B
Rf value =
Distance travelled by substance
Distance travelled by solvent

37. (i)  State the letter of the ink that contained only one coloured dye.
(1)
(ii)  Ink W has been made by mixing two of the other inks together.
State the two inks that could have been mixed to make ink W.

38. (c) A colouring in some sweets was analysed using paper chromatography.
One of the dyes in the colouring moved 2 cm up the paper while the solvent moved 8 cm.
What is the Rf value of this dye?
Put a cross ( ) in the box next to your answer.
(1) A
B 2
C 4
D 6

40. Ions
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An ion is formed when an atom gains or loses electrons and becomes charged: + -
The electron is negatively charged
The proton is positively charged + +
If we “take away” the electron we’re left with just a positive charge:
This is called an ion (in this case, a positive hydrogen ion, also called a cation).

41. Words – full, transfers, positively, negatively, metals, anion, stable
Ionic bonding
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This is where a metal bonds with a non-metal (usually). Instead of sharing the electrons one of the atoms “_____” one or more electrons to the other. For example, consider sodium and chlorine: Na Cl
Sodium has 1 electron on its outer shell and chlorine has 7, so if sodium gives its electron to chlorine they both have a ___ outer shell and are ______. Na +
A _______ charged sodium ion (cation)
A _________ charged chloride ion (______) Cl -
Transfers, full, stable, positively, negatively, anion, metals
Group 1 _______ will always form ions with a charge of +1 when they react with group 7 elements. The group 7 element will always form a negative ion with charge -1.
Words – full, transfers, positively, negatively, metals, anion, stable

42. Draw the arrangement of electrons in the oxide ion. (1)
Q6. When magnesium reacts with oxygen, one magnesium atom and one oxygen atom form one magnesium ion and one oxide ion.
These diagrams show the arrangement of electrons in a magnesium atom and in a magnesium ion.
(i) In the diagram below the arrangement of electrons in an oxygen atom is given.
    Draw the arrangement of electrons in the oxide ion.
(1)

43. (i)
two electrons in first shell and eight in outer shell
dots or crosses or combination of both
(1)

44. Naming compounds
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Rule 1 – When two elements join and one is a halogen, oxygen or sulphur the name ends with ____ide
e.g. Magnesium + oxygen magnesium oxide
Sodium + chlorine
Magnesium + fluorine
Lithium + iodine
Chlorine + copper
Oxygen + iron
KBr
LiCl
CaO
MgS KF

45. e.g. Copper + sulphur + oxygen Copper sulphate
Naming compounds
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Rule 2 – When three or more elements combine and one of them is oxygen the ending is _____ate
e.g. Copper + sulphur + oxygen Copper sulphate
Calcium + carbon + oxygen
Potassium + carbon + oxygen
Calcium + sulphur + oxygen
Magnesium + chlorine + oxygen
Calcium + oxygen + nitrogen
AgNO3
H2SO4
K2CO3

46. Some examples of ionic bonds
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Magnesium chloride: Cl Mg 2+ Mg + Cl - Cl
MgCl2
Calcium oxide: O Ca + 2+ 2-
CaO

47. Balancing ions Determine the formula of these compounds:
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Some common ions:
Sodium – Na+
Potassium – K+
Magnesium – Mg2+
Ammonium – NH4+
Chloride – Cl-
Bromide – Br-
Oxide – O2-
Sulphate – SO42-
Determine the formula of these compounds:
Sodium chloride
Magnesium oxide
Magnesium chloride
Ammonium chloride
Sodium sulphate
Sodium oxide
Answers:
NaCl
MgO
MgCl2
NH4Cl
Na2SO4
NaO

48. Q9.
Magnesium flares provide a bright light in an emergency.
When the magnesium burns it reacts with oxygen to form magnesium oxide.
Explain why magnesium oxide is a compound.
(2)
Answer
Acceptable answers
Mar
An explanation linking the following          two elements / magnesium and oxygen (1)          combined / bonded/(chemically) joined together (1)
ignore mixture ignore reacted together ignore type of bond
(2)

49. Answer
Acceptable answers
Mark
(ii)
An explanation including two of the following points idea of electron(s) transfer in correct direction (1) two (electrons transferred) (1)
  marks can be scored in a diagram any indication of covalent bonding / electron sharing scores 0
(2)

50. Barium sulfate contains barium ions, Ba2+ sulfate ions, SO42–
Q11.
  Barium sulfate contains
barium ions, Ba2+ sulfate ions, SO42–
(i) Give the formula of barium sulfate. (1
(ii) Give the meaning of the term ion.(1)
Answer
Acceptable answers
Mark
(i)
BaSO4
SO4Ba ignore charges unless incorrect
(1)
(ii)
charged particle
charged atom / particle/atom(s) that has gained or lost electrons ignore any stated charges

51. Separating Immiscible Liquids
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“Immiscible” means “two liquids that can’t be dissolved”, e.g. oil and water:
Separating these liquids is fairly easy – you simply allow them to settle and then “tap off” the heavier liquid at the bottom using a separating funnel.

52. A separating funnel is shown.
Q19.
A separating funnel is shown.
Answer
Acceptable answers
Mark
A description to include two from · allow layers to form / separate / liquids to separate(1) · operate tap / OWTTE(1) · run out one layer / OWTTE(1) · pour remaining upper layer from top / run out second layer(1)
  ignore inverted oil/water layers   discard interface
  (2)
The separating funnel can be used to separate two immiscible liquids, such as oil and water.
Describe how you would use a separating funnel to separate two immiscible liquids.
(2)