Electronegativity
Electronegativity measures how strongly an atom attracts bonding electrons.
About this topic
Electronegativity measures how strongly an atom attracts the shared electrons in a bond, on the Pauling scale from about 0.7 (caesium) to 4.0 (fluorine). It increases across a period and decreases down a group, so the most electronegative elements are in the top right, excluding noble gases.
The difference in electronegativity between two bonded atoms predicts the bond type. A difference of less than about 0.4 gives a nonpolar covalent bond, between about 0.4 and 1.7 a polar covalent bond, and above about 1.7 a largely ionic bond. In a polar bond, the more electronegative atom gets a partial negative charge (delta minus) and the other a partial positive (delta plus).
Example: in hydrogen chloride, chlorine (3.0) pulls more strongly than hydrogen (2.1), so the molecule has a dipole. In water, oxygen at 3.5 draws electrons away from the two hydrogens, making the molecule polar, which explains why it dissolves salts. In sodium chloride the difference of about 2.1 means electron transfer.
Electronegativity explains reactivity, polarity and solubility. A misconception is that it is the same as electron affinity or ionisation energy; it applies only to atoms in a bond and has no units.
Key ideas
- Fluorine is highest
- Differences predict bond type
- Increases across a period
Quick check
Use cases: where Electronegativity helps
- Homework: review the key idea behind Electronegativity before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Electronegativity without notes.
- Visual learning: play with the interactive lab to see how Electronegativity changes when you adjust its inputs.
- Teaching a friend: explain Electronegativity in your own words, then compare your version with the key ideas.
Chemistry explains medicine, food, cleaning products, fuels and building materials.
Frequently asked questions
What is Electronegativity?
Electronegativity measures how strongly an atom attracts bonding electrons.
What will I learn in Electronegativity?
Fluorine is highest. Differences predict bond type. Increases across a period.
Is Electronegativity part of Chemistry?
Yes. It is one of 150 Chemistry topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Electronegativity lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Electronegativity?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.