What is the Difference Between Positive and Negative Ion?

06/23/2025 • Maryella Faratro

The difference between positive and negative ions lies in their charge and formation process.

Positive Ions:

  • Carry a positive electrical charge.
  • Form when an atom or molecule loses one or more electrons.
  • Also known as cations.
  • Example: If an atom has more protons than electrons, it becomes a positive ion.

Negative Ions:

  • Carry a negative electrical charge.
  • Form when an atom or molecule gains one or more electrons.
  • Also known as anions.
  • Example: If an atom has more electrons than protons, it becomes a negative ion.

In summary, positive ions have more protons than electrons, while negative ions have more electrons than protons.

Comparative Table: Positive vs Negative Ion

Here is a table comparing the differences between positive and negative ions:

Feature Positive Ions (Cations) Negative Ions (Anions)
Definition An atom or molecule that has lost one or more electrons, resulting in a positive net charge An atom or molecule that has gained one or more electrons, resulting in a negative net charge
Net Charge Positive Negative
Electron-Proton Ratio More protons than electrons More electrons than protons
Ionization Endothermic process Exothermic process
Electrode During Electrolysis Attracted to the anode Attracted to the cathode
Ionic Radius (trend across a period) Decreases from left to right Negative ions are always larger than positive ions in the same period

Read more