What Are Subatomic Particles & Orbitals in an Atom?

By Bjorck DiMarco
What Happens If You Add a Neutron to an Element?
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The ancient Greeks figured out that everything could be broken down into particles that were too small to be seen. They called these particles "atoms," which means indivisible or unable to be divided. We know now that atoms aren't the smallest particles in the universe, but the Greeks were right about the fact that atoms are the building blocks of matter. Atoms are composed of three types of particles that exist within and around the nucleus, or center, of the atom.


Protons are part of the nucleus of an atom. They have a positive electrical, or elementary, charge of 1. There must be at least one proton in the nucleus for an atom to be stable. At one time, it was thought that protons, neutrons and electrons were the smallest bits of matter in the universe, but we discovered that protons are actually composed of three quarks. Two up quarks, which are the lightest type of quark, and one down quark. When three quarks in this configuration combine, they become part of the hadron family and are referred to as baryons. Quarks are held together by what is referred to as "strong force." It is a powerful attractor in the way that electromagnetism is a powerful attractor. The number of protons is also responsible for giving an atom its atomic number. The atomic number, in turn, helps identify the chemical element of the atom, thus creating the Periodic Table of the Elements.


Neutrons are also subatomic particles. They have a slightly larger mass than protons, but no electrical charge. The number of neutrons in an atom's nucleus provides the neutron number in the same way that the number of protons gives an atom its atomic number. The neutron number also determines the isotope. An isotope is a way for scientists to tell the difference between different versions of the same element. For example, look at Carbon-12 and Carbon-14. Carbon-12 is very common. It has 6 protons and 6 neutrons. Carbon-14 is very rare. It has the same 6 protons, but 8 neutrons. While both are carbon elements, they are different isotopes of carbon. While protons can and do exist on their own if divided from an atom, neutrons cannot. They have a lifespan of about 15 minutes after they're split from the atom. In that time, they are said to decay. Splitting a neutron away from an atom's nucleus causes nuclear fission which creates an enormous amount of energy. It is the basis for both nuclear energy and nuclear weapons. Nuclear fusion occurs when the nuclei of two atoms are combined. It also generates energy, but depending on the elements that are combined, some of that energy is reabsorbed.


An electron has a negative electrical charge. It is considered an elementary particle because it has no known sub-particles, like quarks. While protons and neutrons form the nucleus of the atom, electrons, in essence, spin around the nucleus. Sometimes, they collide with positrons, which are an electron's antiparticle, an electron's opposite. It has a positive charge to the electron's negative charge. Since positrons and electrons cannot occupy the same space at the same time, when they collide one of two things happen. They either annihilate each other and in doing so bounce off each other and scatter away or they produce a pair of gamma ray photons. The gamma rays are electromagnetic radiation of a high frequency. It is possible to force electrons to either scatter or annihilate by accelerating the speed in which the electron spins. When man-made, this acceleration plays a part in nuclear fusion and nuclear fission, but in nature, it can be experienced as a lightning strike.


An orbital isn't a particle or any actual part of an atom. An atomic orbital is a mathematical theory that describes the wave-like behavior of a single electron or a pair of electrons in an atom. The theory is used to calculate the probability of finding electrons in a specific region around an atom's nucleus.

About the Author

Bjorck DiMarco has been the Senior Editor at an independent publishing house since 1994. She holds advanced degrees in teaching, English and creative writing, graduating summa cum laude from Tufts University and the University of Massachusetts. DiMarco has also worked in construction, fine woodworking, graphic design and theoretical mathematics.