Scientists discovered that though the atom itself didn't have a charge, it had to be made of particles that had charge. It is these particles that are called subatomic particles.

The subatomic particle with a negative charge is called an electron. The subatomic particle with a positive charge is called a proton.

Let us say that the electron's charge is \(-\mathrm{C}\). The proton's charge is then \(+\mathrm{C}\). (The \(-\) and the \(+\) signs tell you what charge is in the subatomic particle.)