BRAINCAKETrends in First Ionisation Energies Down a Group
The first ionisation energy decreases down a group. Although the nuclear charge increases, its effect is outweighed by the increased radius and to a lesser extent the increased shielding. So the nuclear attraction for the outer electron decreases as you go down the group.
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Key terms in this lesson
- Ionisation
- The loss or gain of electrons by an atom or molecule to form a charged ion.
- First ionisation energy
- The energy needed to remove one electron from each atom of one mole of atoms in their gaseous state to form one mole of gaseous +1 ions, under standard conditions.
- Shielding
- The repulsion of the electron to be removed by the electrons in the inner shells, which reduces nuclear attraction.
- Group
- A vertical column of the periodic table, containing elements with the same number of outer-shell electrons.
More in Periodicity
- Electron Configuration
- Ionisation Energy
- Successive Ionisation Energies
- Trends in First Ionisation Energies Across a Period
- Beryllium and Boron
- Nitrogen and Oxygen
- Metallic Bonding
- Properties of Metals
All 14 lessons in Periodicity · All OCR AS-level Chemistry topics