The Atom
All matter in the universe if made of atoms. The air we breathe and the ground we stand on. The differences in matter are remarkable. Matter can be a solid, liquid or gas.
An atom is the smallest particle that displays the individual characteristics
of an element. What are these atoms
made of and how do they combine to form atoms?
These are the questions we will begin with in this chapter.
The atom is made of subatomic particles, the proton neutron and electron.
A summary of these particles is shown below.
| |
mass (amu) | mass (kg) |
relative charge |
charge in coulombs |
| proton | 1 | 1.67 x 10-27 |
+1 |
1.67 x 10-19 |
| neutron | 1 | 1.67 x 10-27 |
0 |
0 |
| electron | 0.00054 | 9.11 x 10-31 |
-1 |
-1.67 x 10-19 |
Electrons, protons and neutrons were discovered separately in 1897, 1907 and 1932 respectively.