Chemistry

Ionic vs Covalent Bonds: How to Tell the Difference

Tell ionic and covalent bonds apart with a two-line test, worked examples, and the most common mistake.

The quick test

Ionic bonds transfer electrons. Covalent bonds share them.

IONIC

What bond holds NaCl together?

  1. Na is a metal, Cl is a nonmetal
  2. Na gives up 1 electron to Cl
  3. Na⁺ and Cl⁻ attract
Ionic

COVALENT

What bond holds H₂O together?

  1. H and O are both nonmetals
  2. O shares electrons with each H
Covalent (polar, since O pulls harder)

Common mistake

Ionic compounds are made of molecules

Ionic compounds form a crystal lattice. The formula shows the simplest ratio of ions.

Covalent compounds form true molecules.

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