A Quick Look inside the Atom

We have stated that the atom is the smallest particle of an element that can exist and still be that element. We have also stated that if an atom is split in an attempt to make a smaller particle of an element, we would no longer have that element, but instead would have something else. We would have a collection of subatomic particles called protons, neutrons, and electrons. These are the major particles of which all atoms are composed. 

Scientists discovered the existence of these particles and their properties in the late 1800s and early 1900s when some interesting experiments were performed. The modern theory describing these particles, especially the electrons, is complex and highly mathematical. In our present discussion, a very brief physical description of these particles is presented. 

Let us begin with the mass of these particles. Mass refers to the amount of a material. This amount of a material is measured on the Earth s surface by measuring the effect of the pull of gravity on it, or in other words, its weight. References to mass in this discussion can thus be thought of as references to weight. The masses of a proton and a neutron are approximately the same. The mass of an electron is significantly less than that of a proton or neutron. 

FIGURE 1.5 Looking through the mythical microscope at a cross-section of a single atom of an element, we would see that there is a tiny, dense core called the nucleus at the center where the protons and neutrons are found and space surrounding the nucleus where the electrons are found. Microscope image from Shutterstock.com. 

---