Quantization of electric charge means that electric charge exists only in discrete amounts, not as a continuous value. In nature, all electric charges are integer multiples of the elementary charge, e e e, which is approximately 1.602×10−19 1.602 \times 10^{-19} 1.602×10−19 coulombs, the charge of a single proton or the negative of an electron’s charge. For example, a particle can have a charge of +e +e +e, −e -e −e, +2e +2e +2e, or 0 0 0, but never 1.5e 1.5e 1.5e or any fraction of e e e.
This concept arises from experimental observations, like the Millikan oil drop experiment, which showed that the charges on oil droplets were always multiples of a fundamental unit. It’s a cornerstone of modern physics, indicating that charge is not infinitely divisible but comes in packets of e e e. Quarks, discovered later, have fractional charges like +23e +\frac{2}{3}e +32e or −13e -\frac{1}{3}e −31e, but they always combine in particles (like protons or neutrons) to produce integer multiples of e e e in observable matter.