Beginner Topic 90 of 1102 Atomic Structure & Periodicity
Electronegativity
An atom's tendency to attract bonding electrons, highest for fluorine.
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In-depth explanation of Electronegativity
Electronegativity is an atom's tendency to attract the bonding electrons in a covalent bond. It increases across a period and decreases down a group, with fluorine being the most electronegative element. Differences in electronegativity between two bonded atoms predict the polarity of the bond. A large difference leads to ionic character, while a small difference gives a nonpolar covalent bond. Electronegativity is a relative scale and has no absolute unit.
Going deeper: Electronegativity
Key ideas: Electronegativity measures an atom's tendency to attract bonding electrons, with no units on the Pauling scale: F 4.0, O 3.5, N 3.0, Cl 3.0, C 2.5, H 2.1, Na 0.9. It increases across a period and decreases down a group. Difference rules: below 0.4 nonpolar covalent, 0.4 to 1.7 polar covalent, above 1.7 ionic, roughly.
Common mistakes and connections: Students think it is a measurable energy of an isolated atom, but it is a property of an atom in a bond. The ionic cutoff of 1.7 is a guide, not a rule, as some compounds with larger differences are covalent. It decides bond polarity, dipole moments and oxidation numbers.
Visualization of Electronegativity
Across period 3 from Na to Ar, electronegativity increases from 0.93 to Cl at 3.16 as nuclear charge grows and radius shrinks. The interactive lesson shows this as a live animation or chart.
Worked example and use case
In an O-H bond, the difference of 3.44 minus 2.20 gives 1.24, so the bond is strongly polar with partial negative charge on oxygen.
Frequently asked questions about Electronegativity
What is Electronegativity?
An atom's tendency to attract bonding electrons, highest for fluorine.
Is Electronegativity a beginner, intermediate or advanced topic?
Electronegativity is a beginner topic in Atomic Structure & Periodicity. It needs no earlier chemistry lessons and is a good starting point.
What should I learn before Electronegativity?
Study these earlier topics in Atomic Structure & Periodicity first: Successive Ionization Energies, Anomalies in Ionization Energy, Electron Affinity.
What comes after Electronegativity?
The next topics in Atomic Structure & Periodicity are Pauling Scale and Mulliken Electronegativity.
Can I practise Electronegativity with quizzes?
Yes. The interactive lesson includes a self-check question on Electronegativity, and the Atomic Structure & Periodicity quiz draws on every topic in this area.
Where Electronegativity fits in Atomic Structure & Periodicity
Electronegativity is topic 90 of 115 in Atomic Structure & Periodicity.