Science
Electronegativity.
Definition
Electronegativity is a measure of an atom's ability to attract shared electrons in a chemical bond. It increases across a period (left to right) and decreases down a group on the periodic table. Differences in electronegativity determine bond type.
Examples
Real-world.
- 1 Fluorine has the highest electronegativity (3.98) of any element, making it extremely reactive
- 2 The large electronegativity difference between Na and Cl creates an ionic bond in NaCl
- 3 Water is polar because oxygen (3.44) is much more electronegative than hydrogen (2.20)
Key Fact
EN difference: 0-0.4 = nonpolar covalent; 0.4-1.7 = polar covalent; >1.7 = ionic (approximate guidelines).