What is Charge? (The structure of the atom)

(Section 5.2)

 The atom is composed of sub-atomic particles called protons, neutrons and electrons.  In a standard view of the atom, the protons and neutrons are in a small area in the center of the atom called the nucleus.  The electrons circle the nucleus the same way the earth revolves around the sun.  The nucleus is very small compared to the size of the atom.  As an analogy, if the atom where the size of a baseball stadium, then the nucleus would be smaller than a baseball, perhaps closer to the size of a ping pong ball.  You can imagine that most of atom is, in fact, empty space. 



mass (amu)

mass (kg)

relative charge

charge in coulombs
proton 1 1.67 x 10-27


1.67 x 10-19

neutron 1 1.67 x 10-27



electron 0.00054 9.11 x 10-31


-1.67 x 10-19