BRAINCAKETrends in Electronegativity
Electronegativity is the power of an atom to attract the pair of electrons in a covalent bond. It is measured on the Pauling scale, which runs from about 0.7 for caesium and francium up to 4.0 for fluorine, the most electronegative element.
The trends in electronegativity are that it increases across a period and decreases down a group.
Across a period the nuclear charge increases while the shielding stays about the same, because electrons are added to the same main energy level. The atomic radius decreases, so the nucleus attracts the bonding pair more strongly.
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Key terms in this lesson
- Electronegativity
- The attraction of a bonded atom for the pair of electrons in a covalent bond, measured on the Pauling scale.
- Atomic radius
- A measure of the size of an atom, found by measuring the distance between two adjacent nuclei and dividing by two.
- 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 Bonding
- Co-ordinate Bonding
- Metallic Bonding
- Properties of Metals
- Electronegativity
- Polar Covalent Bonds
- Dipole-Dipole Forces
- Van der Waals forces
- Hydrogen Bonding
All 30 lessons in Bonding · All AQA AS-level Chemistry topics