1.
State what is meant by an ionic bond.
[1 mark]
- electrostatic attraction between oppositely charged ions
JD SCIENCE
States of matter and mixtures
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
2.
State what is meant by a covalent bond.
[1 mark]
- a shared pair of electrons between atoms
3.
State what is meant by a metallic bond.
[1 mark]
- attraction between positive ions and delocalised electrons
4.
State what is meant by a giant ionic lattice.
[1 mark]
- repeating 3D structure of ions
5.
State what is meant by a simple molecule.
[1 mark]
- small group of atoms with covalent bonds
6.
State what is meant by graphite.
[1 mark]
- giant covalent structure of carbon in layers
7.
State what is meant by graphene.
[1 mark]
- a single layer of graphite
8.
State what is meant by a polymer.
[1 mark]
- a long chain of repeating monomers
9.
State what is meant by a nanoparticle.
[1 mark]
- a particle 1–100 nm in size
10.
State what is meant by an intermolecular force.
[1 mark]
- a force between molecules, weaker than covalent bonds
11.
Devon is asked about an ionic bond in a Edexcel Chemistry paper.
(a) [2 marks]
- formed by transfer of electrons
(b) [3 marks]
- why ionic compounds have high melting points
12.
Devon is asked about a covalent bond in a Edexcel Chemistry paper.
(a) [2 marks]
- in molecules and giant covalent structures
(b) [3 marks]
- why diamond is hard
13.
Devon is asked about a metallic bond in a Edexcel Chemistry paper.
(a) [2 marks]
- in metals
(b) [3 marks]
- why metals conduct electricity
14.
Devon is asked about a giant ionic lattice in a Edexcel Chemistry paper.
(a) [2 marks]
- e.g. sodium chloride
(b) [3 marks]
- why ionic compounds conduct when molten or dissolved but not as solids
15.
Devon is asked about a simple molecule in a Edexcel Chemistry paper.
(a) [2 marks]
- weak intermolecular forces between molecules
(b) [3 marks]
- why iodine has a low melting point
16.
Devon is asked about graphite in a Edexcel Chemistry paper.
(a) [2 marks]
- layers can slide; delocalised electrons
(b) [3 marks]
- why graphite is a lubricant and a conductor
17.
A cube nanoparticle of side 2 nm. Estimate SA:V compared with a 2 m cube (qualitative then ratio idea).
[3 marks]
- SA:V increases as size decreases
- Final answer: SA:V is much larger for the nanoparticle
18.
How many covalent bonds does a carbon atom form in diamond?
[3 marks]
- Final answer: 4
19.
Na has 11 electrons. Write the ion and the electron configuration of Na⁺.
[3 marks]
- loses 1 electron
- Final answer: Na⁺ 2,8
20.
The formula of magnesium chloride. Mg is 2+ and Cl is 1−.
[3 marks]
- balance charges
- Final answer: MgCl₂
21.
A polymer repeat unit is C₂H₄. What is the empirical formula?
[3 marks]
- Final answer: CH₂
22.
Rf = distance spot / distance solvent. Spot 3.6 cm, solvent 6.0 cm. Rf?
[3 marks]
- Final answer: 0.60
23.
Devon carries out melting-point comparison of ionic vs simple molecular substances. This is a typical Edexcel required-practical style question.
(a) [2 marks]
- Independent: substance type
- Dependent: melting temperature
(b) [2 marks]
- same heating method
- so the test is fair / only one variable is changed
(c) [2 marks]
- uneven heating
24.
Devon carries out testing electrical conductivity of solid, molten and dissolved samples. This is a typical Edexcel required-practical style question.
(a) [2 marks]
- Independent: state of sample
- Dependent: whether the bulb lights
(b) [2 marks]
- same voltage
- so the test is fair / only one variable is changed
(c) [2 marks]
- electrodes not clean
25.
Devon carries out building ball-and-stick models of CH₄, H₂O, CO₂, NaCl. This is a typical Edexcel required-practical style question.
(a) [2 marks]
- Independent: substance
- Dependent: correct geometry
(b) [2 marks]
- same modelling kit
- so the test is fair / only one variable is changed
(c) [2 marks]
- wrong number of bonds
26.
Devon carries out chromatography to identify a mixture of dyes. This is a typical Edexcel required-practical style question.
(a) [2 marks]
- Independent: dye
- Dependent: Rf
(b) [2 marks]
- same solvent
- so the test is fair / only one variable is changed
(c) [2 marks]
- solvent front marked after it evaporates
27.
Compare ionic bonding with covalent bonding.
[4 marks]
- ionic: transfer, metals + non-metals
- covalent: sharing, non-metals
28.
Compare diamond with graphite.
[4 marks]
- diamond: 3D tetrahedral, insulator, hard
- graphite: layers, conductor, soft
29.
Compare a metal with an ionic solid.
[4 marks]
- both high MP
- metal: malleable, conducts as solid; ionic: brittle, conducts when molten
30.
Compare simple molecular with giant covalent.
[4 marks]
- simple: low MP, weak intermolecular forces
- giant: high MP, many strong covalent bonds
31.
Apply your knowledge of graphene to this situation: conducts and is very thin
[3 marks]
- conducts and is very thin
32.
Apply your knowledge of a polymer to this situation: cross-links
[3 marks]
- cross-links