In the chemistry and physics textbooks of nine-year compulsory education, a basic concept is usually mentioned:
Positively charged particles are called cations, and electrons are all negatively charged.
An electron carries one negative charge, a proton carries one positive charge, and the amount of charge they carry is the smallest unit of electric charge.
The scientific term is elementary charge, with a value of 1.6*10^-19C.
For high school knowledge level, this concept doesn't have much error.
But in reality....
There are positively charged electrons in the world.
It is a form of antimatter.
Before discussing antimatter, it's important to distinguish antimatter from dark matter.
Many friends easily confuse these two concepts.
Actually, antimatter and dark matter are two different concepts, their similarity mainly lies in their names.
