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Year 10
OCR
Higher

Properties of giant ionic structures

I can describe the properties of ionic compounds and explain how they result from the ionic structure model.

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New
New
Year 10
OCR
Higher

Properties of giant ionic structures

I can describe the properties of ionic compounds and explain how they result from the ionic structure model.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. In a giant ionic structure there are strong electrostatic forces in all directions between oppositely charged particles.
  2. Ionic compounds have high melting points and high boiling points because strong ionic bonds need to be broken.
  3. Most ionic substances can dissolve in water.
  4. The ions of ionic compounds dissolved in water are free to move around and the solution can conduct electricity.
  5. The ions of ionic compounds that are in the liquid state are free to move around and the liquid can conduct electricity.

Common misconception

There are several misconceptions associated with properties such as when something dissolves it disappears, electrical conductivity is a flow of electrons rather than charge.

When discussing electrical conductivity, emphasise the idea of electrical conductivity being a flow charge with ions behaving as charge carriers. The electron transfer that occurs during ion formation is nothing to do with conductivity.

Keywords

  • Conductor - A material which transfers thermal energy easily; electrical conductors allow charge to flow through them.

  • Melting point - The temperature at which a substance changes from solid state to a liquid state.

  • Charge carrier - A particle that enables electrical conductivity, such as delocalised electrons or free–moving ions.

  • Dissolve - When a substance's particles separate and spread throughout the particles of a solvent resulting in it no longer being seen.

  • Solubility - The ability of a substance to dissolve in a particular solvent creating a solution; how well a solute dissolves in a solvent.

Ask the students to carry out simple experiments or do teacher demonstrations to illustrate the properties of ionic compounds such as high melting and boiling points, conductivity and solubility.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.
What does the symbol (aq) stand for?
Correct Answer: aqueous, Aqueous
Q2.
Which of the following describes an ionic bond?
The transfer of electrons between atoms to form oppositely charged ions.
Correct answer: The electrostatic force of attraction between oppositely charged ions
The sharing of electrons between atoms to form molecules.
A regular lattice of positive ions in a sea of delocalised electrons.
Q3.
How is the cation Mg²⁺ formed?
A magnesium ion donates two electrons.
Correct answer: A magnesium atom donates two electrons.
A magnesium ion accepts two electrons.
A magnesium atom accepts two electrons.
Q4.
Lithium is a metal found in Group 1, Period 2 on the periodic table. What is the charge on a lithium ion?
Correct answer: Li⁺
Li²⁻
Li⁻
Li²⁺
Q5.
Why do non–metal atoms gain electrons to form anions?
Correct answer: To achieve a full outer shell of electrons.
Correct answer: To become more stable.
To become negatively charged.
To form an ionic bond.
To become electrostatically attracted to cations.
Q6.
A phosphorus atom has 15 electrons in total. How many electrons are there in the outer shell of a phosphorus atom?
Correct Answer: 5, five

Exit quiz

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6 Questions

Q1.
Match the following terms to the correct definitions.
Correct Answer:electrical conductivity,A measure of how well a material conducts electricity.

A measure of how well a material conducts electricity.

Correct Answer:thermal conductivity,A measure of how well a material transfers energy when heated.

A measure of how well a material transfers energy when heated.

Correct Answer:melting point,Temperature at which a substance changes from solid to a liquid state.

Temperature at which a substance changes from solid to a liquid state.

Correct Answer:charge carrier,A particle that enables electrical conductivity.

A particle that enables electrical conductivity.

Correct Answer:Solubility,How well a solute dissolves in a solvent

How well a solute dissolves in a solvent

Q2.
Which of the following ionic substances is not a good electrical conductor?
Correct answer: NaCl(s)
NaCl(aq)
NaCl(l)
Q3.
In a giant ionic structure, there are strong electrostatic forces in all directions between charged particles.
Correct Answer: oppositely, opposite
Q4.
Why do ionic compounds have high melting and boiling points?
Correct answer: A large amount of energy is needed to overcome the strong ionic bonds.
Correct answer: Energy is needed to overcome the electrostatic attraction between the ions.
Large amounts of energy are needed to transfer the electrons between the atoms.
Energy is needed to melt the ions to form a liquid.
Q5.
Why are most ionic compounds soluble in water?
Correct answer: Water molecules are attracted to the ions in the lattice.
Correct answer: The ionic forces of attraction are overcome.
A large amount of energy is needed to break the ionic bonds.
The ionic compound melts when in contact with water.
Q6.
Why is the melting point of magnesium oxide, MgO, higher than sodium chloride, NaCl?
Correct answer: The electrostatic attraction between magnesium ions and oxygen ions is stronger.
Sodium forms ions with a higher charge than magnesium.
Correct answer: Oxygen forms ions with a higher charge than chlorine.
More energy is needed to overcome the bond between sodium and chlorine ions.