Starter quiz
- What does the symbol (aq) stand for?
- 'aqueous' ✓
- Which of the following describes an ionic bond?
- The transfer of electrons between atoms to form oppositely charged ions.
- 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.
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- How is the cation Mg²⁺ formed?
- A magnesium ion donates two electrons.
- A magnesium atom donates two electrons. ✓
- A magnesium ion accepts two electrons.
- A magnesium atom accepts two electrons.
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- Lithium is a metal found in Group 1, Period 2 on the periodic table. What is the charge on a lithium ion?
- Li⁺ ✓
- Li²⁻
- Li⁻
- Li²⁺
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- Why do non–metal atoms gain electrons to form anions?
- To achieve a full outer shell of electrons. ✓
- To become more stable. ✓
- To become negatively charged.
- To form an ionic bond.
- To become electrostatically attracted to cations.
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- A phosphorus atom has 15 electrons in total. How many electrons are there in the outer shell of a phosphorus atom?
- '5' ✓
Exit quiz
- Match the following terms to the correct definitions.
- electrical conductivity⇔A measure of how well a material conducts electricity. ✓
- thermal conductivity⇔A measure of how well a material transfers energy when heated. ✓
- melting point⇔Temperature at which a substance changes from solid to a liquid state. ✓
- charge carrier⇔A particle that enables electrical conductivity. ✓
- Solubility⇔How well a solute dissolves in a solvent ✓
- Which of the following ionic substances is not a good electrical conductor?
- NaCl(s) ✓
- NaCl(aq)
- NaCl(l)
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- In a giant ionic structure, there are strong electrostatic forces in all directions between ______ charged particles.
- 'oppositely' ✓
- Why do ionic compounds have high melting and boiling points?
- A large amount of energy is needed to overcome the strong ionic bonds. ✓
- 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.
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- Why are most ionic compounds soluble in water?
- Water molecules are attracted to the ions in the lattice. ✓
- 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.
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- Why is the melting point of magnesium oxide, MgO, higher than sodium chloride, NaCl?
- The electrostatic attraction between magnesium ions and oxygen ions is stronger. ✓
- Sodium forms ions with a higher charge than magnesium.
- Oxygen forms ions with a higher charge than chlorine. ✓
- More energy is needed to overcome the bond between sodium and chlorine ions.
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Worksheet
Presentation
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Lesson Details
Key learning points
- In a giant ionic structure there are strong electrostatic forces in all directions between oppositely charged particles.
- Ionic compounds have high melting points and high boiling points because strong ionic bonds need to be broken.
- Most ionic substances can dissolve in water.
- The ions of ionic compounds dissolved in water are free to move around and the solution can conduct electricity.
- 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 conductor is a substance that allows charge or energy to flow through it easily due to the presence of delocalised electrons.
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.