Atoms are mysterious!
Democritus, born in 460 BC Greece, first proposed the concept of atoms.
He daringly said that the physical universe around us is composed of fundamental indivisible components.
Hundreds of years later, this was what led John Dalton, an English chemist, physicist, and meteorologist, to formulate his Atomic Theory.
He proposed that elements are made of extremely small particles called atoms.
He said that atoms of different elements differ in size, mass, and other properties, cannot be subdivided, created, or destroyed, and are combined, separated, or rearranged in chemical reactions.
Most did not believe in such a fairy tale for a long time!
Building on top of these foundations, J.J. Thompson in 1897, discovered electrons as a stream of particles being emitted from the cathode in his experiments.
And then, protons (the positive particles in an atom’s nucleus) were discovered by E. Rutherford and neutrons (the neutral particles in an atom’s nucleus) were discovered by J. Chadwick.
Eventually, the theory gained more acceptance but despite these marvelous discoveries, no one had still ever seen an atom.
This was because atoms are really tiny!
How tiny, you would ask?
Atoms have a radius of about 0.1 nm (nanometers), or 0.0000000001 meters (1 × 10 -10 m).
This video by Kurzgesagt — In a Nutshell might help you realize how small this number is.
By the way, electrons don’t revolve around the nucleus like in our solar system.