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Successive Ionisation Energies

Successive ionisation energies increase because the remaining electrons are pulled closer to the nucleus after each electron is lost and the nuclear attraction on the remaining electrons increases.
The second ionisation energy is the energy required to remove one electron from each ion in one mole of gaseous 1+ ions of an element to form one mole of gaseous 2+ ions.
Mg+(g) → Mg2+(g) + e-

Large jumps in ionisation energies provide evidence for electrons existing in shells. A large jump indicates the electron is being removed from a shell closer to the nucleus.
Successive ionisation energies of period 2 elements in kJmol-1
e-1st I.E.2nd I.E.3rd I.E.4th I.E.5th I.E.6th I.E.7th I.E.8th I.E.9th I.E.
Li15207300
Be2900176014850
B38002430366025020
C4109023504620622037830
N51400286045807480944053270
O61310339053007470109801333071330
F7168033706050841011020151601787092040
Ne8208039506120937012180152402000023070115380

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Specification: AQA Chemistry (7404), AS-level, 3.2.1.2 Physical properties of Period 3 elements. Topic: Periodicity.

Key terms in this lesson

Mole
The amount of substance that contains as many particles as there are atoms in exactly 12g of carbon-12.
Group
A vertical column of the periodic table, containing elements with the same number of outer-shell electrons.
Period
A horizontal row of the periodic table, containing elements with the same number of electron shells.

More in Periodicity

All 14 lessons in Periodicity · All AQA AS-level Chemistry topics