Difference Between Ions and Electrons

Ions vs Electrons

There are many differences between electrons and ions; size, charge, and nature are some of them. Electrons are negatively charged micro particles and ions are either negatively or positively charged molecules or atoms. Properties of electrons are explained using “quantum mechanics.” But properties of ions can be explained using general chemistry. Electron (symbol: β- or ℮-) is a sub-atomic particle, and it does not have sub-particles or sub-structures. But, ions can have even more complex structures with sub-components.

What is an Electron?

Electron was first discovered by J.J. Thompson in 1906 while he was working with cathode rays that are called electron beams. He found that electrons are negatively charged micro particles. He used to call them “corpuscles.” Moreover, he found that the electron is an element of the atom and it is over 1000 times smaller than the Hydrogen atom. The size of the electron is approximately 1/1836 of a proton.

According to the Bohr’s theory, electrons orbit around the nucleus. But later, as a result of scientific experiments, it was found that electrons behave more like electromagnetic waves than orbiting particles.

Difference Between Ions and Electrons

What is an Ion?

As said before, ions are either negatively or positively charged molecules or atoms. Both atoms and molecules can form ions by accepting or removing electrons. They gain positive charge (K+, Ca2+, Al3+) by removing electrons and gain negative charge (Cl-, S2-, AlO3-) by accepting electrons. When an ion is formed, the number of electrons is not equal to the number of protons. However, it does not change the number of protons in the atom/molecule. The gain or loss of one or more electrons has a significant effect on the physical and chemical properties of the parental atom/molecule.

Ions vs Electrons

What is the difference between Electrons and Ions?

• Electric Charge:

• Electrons are considered as negatively charged elementary particles but can be either positive or negative.

• Ions with a positive charge are called “positive ions” and similarly ions with a negative charge are called “negative ions.” Ions are formed by accepting or donating electron(s).

- Examples of positive ions: Na+, Ca2+, Al3+, Pb4+, NH4+

– Examples of negative ions: Cl-, S2-, AlO3-

• Size:

• Electrons are extremely smaller particles compared to the ions.

• The size of ions varies depending on several factors.

• The size of an electron is a fixed value; it is about 1/1836 of a proton.

• Atomic Structure:

• Electrons are not polyatomic or monatomic. Electrons do not combine with each other to form compounds.

• Ions can be polyatomic or monatomic; monatomic ions contain only one atom whereas polyatomic ions contain more than one atom.

- Monatomic ions: Na+, Ca2+, Al3+, Pb4+

- Polyatomic ions: ClO3-, SO43-

• Particles:

• Electrons are micro particles and possess wave-particle properties (Wave-particle duality).

• Ions are considered as particles only.

• Elements:

• Electrons are considered as elemental particles. In other words, electrons cannot be divided into smaller components or substructures.

• All the ions have sub-components. For example, polyatomic ions contain various atoms; atoms can be further sub-divided into neutrons, protons, electrons, etc.

• Properties:

• All electrons have the similar wave-particle properties, which can be explained using quantum mechanics.

• Chemical and physical properties of ions vary from ion to ion. In other words, different ions have different chemical and physical properties.


Images Courtesy:

  1. Pair production by  Davidhorman (CC BY-SA 3.0)
  2. An electrostatic potential map of the nitrate ion (NO3−) via Wikicommons (Public Domain)