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HIA International — Grade 8

Unit 1: Photosynthesis and the carbon cycle

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Unit 2: Properties of materials

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Unit 3: Forces and energy

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Unit 4: Maintaining life

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Unit 5: Reactivity

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Unit 6: Sound and space

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Unit 7: Genes and inheritance

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Unit 8: Rates of reaction

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Unit 9: Electricity

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Quiz

Simple and Giant Structures – Quiz

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Simple and Giant Structures HIA Science quiz: free practice for HIA International. Work through this Simple and Giant Structures HIA Science quiz and get instant feedback on every answer. If you get stuck, review the 20.11 Simple and Giant Structures – Notes lesson. More practice: HIA International — all units. Syllabus: Cambridge Lower Secondary programme.

  • Questions count: 50
  • Passing grade: A-
  • Time limit:
Start Quiz
1.
What is a simple molecular structure?
Small separate molecules
A continuous metal lattice
Positive ions only
One giant atom
2.
What is a giant structure?
Billions of atoms or ions joined in a repeating arrangement
One small molecule
A mixture of unbonded gases
A single nucleus
3.
What does the word lattice mean?
A regular repeating arrangement of particles
A random collection of molecules
A moving stream of electrons
A single covalent bond
4.
What holds separate simple molecules near one another?
Weak intermolecular forces
Metallic bonds
Nuclear forces
Strong ionic bonds inside every molecule
5.
Why do many simple molecular substances have low melting points?
Only weak forces between molecules must be overcome
Their nuclei are removed easily
All their covalent bonds are weak
They contain free ions
6.
During melting of a simple molecular substance, what is mainly overcome?
Forces between molecules
Protons inside nuclei
Covalent bonds within each molecule
The atoms themselves
7.
Why does carbon dioxide have a very low melting point?
Its small molecules separate when weak intermolecular forces are overcome
It contains mobile ions
Its carbon atoms form metal layers
It has no covalent bonds
8.
Which is an example of a simple molecular substance?
Water
Diamond
Graphite
Sodium chloride lattice
9.
What particles occupy a giant ionic lattice?
Positive and negative ions
Neutral molecules only
Free protons and neutrons
Carbon layers only
10.
Why does solid sodium chloride not conduct electricity?
Its ions are fixed in the lattice
It contains no charged particles
Its electrons have no energy
It is made of molecules
11.
Why does molten sodium chloride conduct electricity?
Its ions are free to move
Its atoms become electrons
Its molecules gain nuclei
Its covalent bonds conduct
12.
Why can sodium chloride solution conduct electricity?
Dissolved ions can move through the solution
Water becomes a metal
The ions lose all charge
The salt forms diamond
13.
What happens to ions in an ionic solid?
They vibrate about fixed positions
They flow freely through the lattice
They disappear
They form separate molecules
14.
Why do giant ionic substances usually have high melting points?
Strong electrostatic attractions act throughout the lattice
Weak forces act between tiny molecules
Their ions have no charge
Their nuclei melt first
15.
Which property best fits sodium chloride?
High melting point and conduction when molten or dissolved
Low melting point and solid-state conduction
Very low melting point and free electrons
High melting point and no charged particles
16.
Why can magnesium oxide have a higher melting point than sodium chloride?
Its doubly charged ions attract more strongly
It contains weaker forces
It is a simple molecule
Its ions are uncharged
17.
What is a giant covalent structure?
A continuous network of atoms joined by covalent bonds
Separate ions floating in water
Small molecules joined by ionic bonds
Layers held by metallic bonds only
18.
Which element forms both diamond and graphite?
Carbon
Sodium
Chlorine
Magnesium
19.
How many covalent bonds does each carbon atom form in diamond?
Four
One
Two
Six
20.
Why is diamond extremely hard?
Strong covalent bonds extend in a rigid three-dimensional network
Weak intermolecular forces hold layers
Mobile ions lock together
It contains liquid carbon
21.
Why does diamond not conduct electricity?
It has no mobile charged particles or free electrons
Its carbon atoms have no electrons
It melts too easily
Its layers slide
22.
How are carbon atoms arranged in graphite?
In covalently bonded layers
As separate carbon dioxide molecules
As alternating positive and negative ions
In isolated atoms only
23.
Why does graphite conduct electricity?
It has delocalised electrons that can move along the layers
Its carbon ions move between layers
Its molecules are charged
Its nuclei flow through the solid
24.
Why can graphite layers slide over one another?
Only weak forces act between the layers
Covalent bonds within each layer are weak
The layers are liquid
Positive ions repel every atom
25.
Why does graphite still have a very high melting point?
Many strong covalent bonds within its giant structure must be broken
Its weak layer forces require enormous energy
It contains sodium ions
It has separate small molecules
26.
Which statement about molecular melting is correct?
Molecules separate without breaking their internal covalent bonds
Every atom loses its nucleus
Ions become uncharged
All covalent bonds inside molecules break
27.
What must be broken to melt a giant covalent substance?
Many strong covalent bonds in the network
Only weak forces between molecules
No forces at all
Bonds inside a single ion
28.
An unknown substance has a low melting point and does not conduct. What structure is most likely?
Simple molecular
Giant ionic
Diamond-like giant covalent
Graphite-like giant covalent
29.
An unknown solid has a high melting point and conducts only when molten. What is it most likely?
Giant ionic
Simple molecular
Diamond
Graphite
30.
An unknown solid has a very high melting point and conducts while solid. Which model fits best?
A graphite-like giant covalent structure
A diamond-like structure
A simple molecular structure
A sodium chloride solid
31.
An unknown solid has a very high melting point and never conducts. Which model fits best?
A diamond-like giant covalent structure
A graphite-like structure
A molten ionic lattice
A simple molecular liquid
32.
What are the particles in a simple molecular substance?
Small molecules
A sea of metal ions only
Alternating nuclei
Free neutrons
33.
What are the mobile charge carriers in molten ionic compounds?
Ions
Molecules
Neutrons
Fixed atoms
34.
What are the building particles in diamond?
Carbon atoms
Carbon dioxide molecules
Carbon ions in solution
Water molecules
35.
What general condition is required for electrical conduction?
Charged particles must be able to move
Every particle must be neutral
The substance must have a low melting point
All bonds must be broken
36.
Why is the presence of ions not enough for an ionic solid to conduct?
The ions cannot move while fixed in the lattice
The ions have no electrical charge
The ions turn into molecules
The electrons leave the nuclei
37.
Why do simple molecular substances usually not conduct?
They usually have no mobile charged particles
Their molecules are always frozen
They contain only free ions
Their intermolecular forces carry current
38.
Which charge carrier moves through graphite?
Delocalised electrons
Carbon nuclei
Chloride ions
Water molecules
39.
What mainly determines a substance's melting point and conductivity?
Its structure and bonding
Its name
Its colour only
The size of its sample only
40.
Which requires more energy to separate?
Particles in a giant lattice
Separate small molecules with weak attractions
Gas molecules far apart
Unbonded atoms in a dilute gas
41.
Which description does not represent a lattice?
A few separate water molecules
A repeating ionic arrangement
A giant covalent network
A regular three-dimensional pattern
42.
Which phrase best describes a giant ionic lattice?
A three-dimensional repeating pattern of oppositely charged ions
A row of neutral molecules
Separate carbon layers with free electrons
One large molecule floating freely
43.
Why is the word giant used for diamond?
Its bonding continues through an enormous network of atoms
Each carbon atom is physically huge
It contains giant nuclei
It is always a large visible crystal
44.
Compared with sodium chloride, why are attractions in magnesium oxide often stronger?
The ions carry charges of greater magnitude
Magnesium oxide has no ions
Sodium chloride is covalent
Magnesium oxide contains weak molecules
45.
Which substance should melt more easily?
Water
Diamond
Magnesium oxide
Graphite
46.
Which comparison is correct?
Carbon dioxide is simple molecular, while graphite is giant covalent
Both are giant ionic
Both contain mobile ions when solid
Graphite is simple molecular
47.
A substance melts easily and remains an electrical insulator. Which explanation is best?
It consists of small neutral molecules with weak forces between them
It has a giant ionic lattice with moving ions
It contains a giant network of free electrons
It has extremely strong bonds throughout
48.
A substance has a high melting point, does not conduct as a solid, but conducts when dissolved. What is it?
An ionic compound
A simple molecular substance
Diamond
Graphite
49.
A solid conducts electricity and consists of strong carbon layers. What is it?
Graphite
Diamond
Water
Sodium chloride
50.
Which summary is scientifically correct?
Properties follow structure: strong extended bonding raises melting point, and mobile charges allow conduction
All covalent substances conduct
All molecular substances have high melting points
Every ionic solid conducts while solid
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Part of Unit 2: Properties of materials — see every lesson and quiz in this unit.
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