Topic 5 – Atoms and Isotopes

Isotopes of lithium

Image from “Russell’s Blog” which you can access by clicking on the image

Last time we talked about the important parts of atoms – protons and electrons – and how they come together to define the unique properties of every element.  Now let’s tackle the one remaining part, which is how neutrons fit into the mix.  Remember, neutrons and protons are practically the same thing in terms of mass, except the proton carries a positive charge.  The neutron even says it in the name.  It is neutral, meaning no charge, just mass.

That mass is what the neutron brings to an atom.  The mass of an atom is dictated by the number of protons and neutrons.  The identity of an atom is defined by the number of protons, so a given element will always have the same number of protons.  Lithium always has three protons, carbon has six protons, iron has 26 and so on.  The number of protons is so important, it is called the atomic number and you will find it on every periodic table you will see.   Continue reading