Protons and Neutron

    In the nucleus of an atom, there are two different types of subatomic particles which can be found, protons and neutrons.   These two particles are approximately equal in mass; a proton (or a neutron) weighs about 2x10-23 grams each.  Although they weigh so little, protons and neutrons make up 99.9% of the mass of an atom, so an atoms massive is also quite small.  Though their location and mass are the same, there are several differences between the two particles.

Protons:
    Protons are subatomic particles with a positive electrically charge.  If an atom is neutral in charge, there must be an equal number of protons and electrons in the atom; a neutral charge is typically for any element found in nature.  Elements are described and separated by the number of protons in their nucleus.  The number of protons in each atom of an element is given by the element's Atomic Number, which can be found on the Periodic Table.  The proton was first identified by Wilhelm Wien in 1902, and its existence was then confirmed by J.J. Thompson in 1906.

Neutron:
    Neutrons are subatomic particle with no net electrically charge.  The number of neutrons in one atom  of an element can be found by subtracting the Atomic Number of element  from it Mass Number (the total number of protons and neutrons in an atom).  Elements can contain any number of neutrons in their nucleus.  Hydrogen does not have an neutrons in its nucleus (the only element with this characteristic) but other heavier atoms have more neutrons than protons in their nuclei.  The neutron was first discovered by Sir James Chadwick in 1932..

Return to the Web of Ideas

Return to Directory