The Most Basic Unit of Matter: The Atom

Matter Is Made of Atoms

Atom, artwork
Science Photo Library - ANDRZEJ WOJCICKI / Getty Images

Question: What is the most basic building block of matter?

Answer: The basic unit of all matter is the atom. The atom is the smallest unit of matter that can't be divided using any chemical means and the building block that has unique properties. In other words, an atom of each element is different from an atom of any other element. However, even the atom can be broken into smaller pieces, called quarks.

Structure of the Atom

An atom is the smallest unit of an element. There are 3 parts of an atom:

  • proton - positive electrical charge, found in the nucleus of an atom
  • neutron - neutral or no electrical charge, found in the nucleus of an atom
  • electron - negative electrical charge, found circling the nucleus

The size of the proton and neutron are similar, while the size (mass) of the electron is much, much smaller. The electrical charge of the proton and electron are exactly equal to each other, just opposite to each other. The proton and electron attract each other. Neither the proton nor the electron is attracted or repelled by the neutron.

Atoms Consist of Subatomic Particles

Each proton and neutron consist of even smaller particles called quarks. The quarks are held together by particles called gluons. An electron is a different type of particle, called a lepton.

  • proton - consists of 2 up quarks and 1 down quark
  • neutron - consists of 2 down quarks and 1 up quark
  • electron - is a lepton

There are other subatomic particles, too. So, at the subatomic level, it's difficult to identify a single particle that could be called the basic building block of matter. You could say quarks and leptons are the basic building blocks of the matter if you like.

Various Examples of Matter