The Difference Between Atoms, Molecules, And Particles

“We must be clear that when it comes to atoms, language can be used only as in poetry. The poet, too, is not nearly so concerned with describing facts as with creating images and establishing mental connections.” —Niels Bohr

In A Nutshell

Atoms are the smallest pieces of matter; they are made of particles (protons and electrons). When atoms are grouped together, these groups are called molecules (the smallest pieces of compounds).

The Whole Bushel

You probably think of atoms, molecules, and particles as all being extremely small pieces of matter. This is not exactly accurate; while atoms are matter—the smallest pieces of matter you can find—molecules are the smallest bits of compounds. And particles aren’t matter, but the building blocks of it.

For example, copper is an element. A copper atom is the smallest piece of copper that exists. Hydrogen is also an element; two hydrogen atoms and one oxygen atom combine to form a molecule of water, which is a compound.

While atoms are the tiniest bits of matter, they are made of the sub-atomic building blocks of matter—protons and electrons—revolving around a nucleus. The “atomic number” of an element, as seen on a periodic chart, refers to the number of protons contained in one atom of that element.

Show Me The Proof

Building Blocks: Atoms
What is the difference between atoms and elements?
The Difference Between Atoms, Ions, Molecules and Compounds

  • Hillyard

    OK learned something new again. That’s always cool, I must admit this is not something that has ever kept me up at night.

    • bhaggen

      The only thing that WILL keep me up at night is an errant erection.

      • Cameron D-B

        thanks, you just made my day (;

        • bhaggen

          Thanks, now I’ll be up all night. 😉

  • Giyan

    We the neutrons of this universe are most upset that the writer of this article has completely ignored our existence.

    • cyberpal


    • KenneyP

      We the PROtrons of the everything else other than the neutrons of the universe are more than more upset at the writer of the blog to this writer of this article that has completely ignored the existence of the existence. We NOW are going to hire an attorney to file a class-action lawsuit against the Obama administration to repeal the Obamacare without a replacement plan because molecules discriminate against atoms for not having an equal amount of atoms. We DEMAND that water be made up of TWO (2) atoms of oxygen just like hydrogen.

  • rhijulbec

    Thank you for the tidbit, very interesting.

  • Frank Blackstone

    Light is a particle beam , Shine a light through a membrane , in theory does a part of that Membrane travel with the light beam however Minuit in structure . Has this theory been studied and address’d ?

  • Paxton

    Sorry, KnowledgeNuts, but we think you’re incorrect about the fact the atoms are the smallest pieces of matter, and that particles are the building blocks of it. If particles are the building blocks of an atom, surely atoms wouldn’t then be the smallest. If your definition is true, particles would be nothing – they wouldn’t exist.

    • Luke

      I agree with Paxton, particles wouldn’t exist if they are the building blocks of an atom but yet an atom is the smallest thing in existence. It doesn’t make sense!

      • Robert Green

        Particles do exist, but what makes up particles? What is the makeup of a nucleus? The void of space is nothing?……ermm excuse me! It is something, otherwise what would our planet be floating around in. We just cant observe it, the same as the naked eye cant observe the oxygen we breath.

        • Guy Bobson

          Definitely right Luke, Paxton and Robert – I thoroughly agree with you!

        • W.C. McArthur

          Quarks are the subatomic particles that compose the protons and neutrons that create the nucleus of an atom. The electrons that rotate around the nucleus of the atom belong to a group of fundamental subatomic particles known as leptons.

    • Arun

      I understand it like – if the measurement unit is matter – > atom is the smallest. If you break further you get particle but its not matter. Similarly if the measurement unit is compound the smallest unit is molecule….

  • Hinzmaster

    You’re wrong about particles being the smallest things in the universe, it’s Angela Merkel’s brain

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  • SuperHero Blogger

    Let’s fire up this particle accelerator and see if we can’t become the reverse flash lol Just kidding. All joking aside though there is a real particle accelerator but the name is called Hadron Collider. Correct me if I’m wrong, but it supposedly takes particles and smashes them together at least at the speed of sound if not at the speed of light. They are trying to punch a hole in the space-time continuum into another dimension. Pretty freaky.