How to Find Protons, Neutrons and Electrons

In an attempt to understand the basic designing of atoms, it is important to gain information about the methodology to find out protons, neutrons, and electrons. This article deals with the basic methods to find the number of subatomic particles in an atom.
Elementary physics and chemistry deal with atoms, electrons, and protons. An understanding of the basic concepts of these fundamental parts of an atom can help us to decipher intricate chemical processes in this world. Moreover, by knowing simple methods of finding the number of protons, neutrons and electrons, we can understand from a closer perspective, how a change in the number of these particles affects the physical and chemical properties of chemical elements.
  • Electrons: It is a subatomic particle that carries a negative charge (-1). It was discovered by a team of British physicists including Sir J.J Thompson, in 1897.
  • Proton: The positively charged particle proton (+1 charge) is just like a positive hydrogen ion. Ernest Rutherford established the existence of protons in 1918 by sending alpha particles through nitrogen gas.
  • Neutron: They are neutral subatomic particles found in the center of the nucleus. They were discovered by James Chadwick in 1932.
Finding Protons Neutrons and Electrons In an Element

Be it physics or chemistry, students of elementary science need to be aware of the ways on how to find protons, neutrons, and electrons. Some simple fundamentals that students must be aware of are as follows:
  • Number of Protons = Atomic Number
  • Number of Electrons = Number of Protons = Atomic Number
  • Number of Neutrons = Mass Number - Atomic Number
  • Mass Number = Sum of Protons and Neutrons
Finding Protons, Neutrons, and Electrons of Isotopes

Isotopes are atoms of the same element with the same proton number, but different number of neutrons. For example, carbon - 12, carbon - 13 and carbon - 14 are three isotopes of Carbon, each having 6 electrons. The neutron number however are, 6, 7, and 8, respectively, in each of these Carbon isotopes. To know how to find protons, neutrons, and electrons in an isotope, let us consider the example of Chlorine isotopes, Chlorine - 35 (17Cl35) and Chlorine - 37 (17Cl37)

Chlorine - 35 (17Cl35)

Number of Electron = Number of Proton = Atomic Number = 17
Mass Number = 35
Number of Neutron = Mass Number - Atomic Number = 35 - 17 = 18

If we consider, Chlorine - 37 (17Cl37)

Number of Electron = Number of Proton = Atomic Number = 17
Mass Number = 37
Number of Neutron = Mass Number - Atomic Number = 37 - 17 = 20

Finding Protons, Neutrons, and Electrons of Ions

It is essential to know about cations and anions, before we learn the simple method to find the protons, electrons, and neutrons in them.
  • Cations: Ions having positive charges are called cations. They're lost after the loss of electrons in an atom.
  • Anion: These are negatively charged ions, which are formed as a result of addition of extra electrons in an atom.
Consider the case of Na+.

As per atomic structure of Sodium, we know that atomic number of sodium (Na) is 11. However, since the sodium ion is carrying a positive charge, it must have either gained a proton, or lost an electron. Since it is not possible for Na to gain one proton, as it will become Magnesium, it must have lost one electron. Hence, the original number of electrons and protons in Sodium is equal to 11, but as it has lost one electron, the number of electrons = number of protons = atomic number = 10.

Similarly, the number of neutrons in Na+ = Mass Number - Atomic Number = 23 - 10 = 13

It is simple to know the number of protons, electrons, and neutrons by using the periodic table. This table has the atomic and mass number written on it. By attempting to learn more about how to find these subatomic particles in several other elements, students can master this simple technique.