Ionisation Energy
Ionisation energy measures the energy required to remove an electron from a gaseous atom or ion. These pages build from the definition of first ionisation energy through to successive ionisation energy patterns and the main periodic trends across a period and down a group.
Ionisation energy and periodic trends are here. Metallic bonding and giant covalent lattices are on the Bonding and Structure pages linked below.
Revision Notes
4 revision notes, in the order the specification teaches them.
Introduction to Ionisation Energy
Revise the definition of first ionisation energy, state symbols and the factors that affect electron removal.
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Successive Ionisation Energies
Use successive ionisation energy data to identify electron shells, group number and large jumps between energy levels.
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Trends in a Period
Explain why first ionisation energy generally increases across a period, including the small drops at key points.
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Trends in a Group
Explain why first ionisation energy decreases down a group as shielding and atomic radius increase.
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Ionisation Energies Map
OCR A Level Chemistry A · 3.1.1 Periodicity · Ionisation energies
Ionisation energies on one A4 page: first and successive IEs, the factors, trends across periods and down groups, and melting points across Periods 2 and 3.
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3.1.1
- c (i) a
explanation of the trend in first ionisation energies across Periods 2 and 3, in terms of attraction, nuclear charge and atomic radius
Revise - c (i) b
explanation of the trend in first ionisation energies down a group, in terms of attraction, nuclear charge and atomic radius
Revise - c (ii) a
prediction from successive ionisation energies of the number of electrons in each shell of an atom
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