Question

Who discovered atoms first?

Answer 1

Atoms are regarded as the building blocks of matter. Atoms join to form molecules. It is the smallest unit of ordinary matter that forms a chemical element. Atoms can also be defined as the smallest possible amount of matter which still retains its identity as a chemical element.

Complete answer:
We have defined atoms as the smallest unit of the matter. Atoms combine to form molecules which then interact to form solid, gases or liquids.
The first person to discover an atom was a Greek philosopher Democritus. He described atoms as the fundamental or basic unit. According to his theory;
All matter consists of atoms, which are the bits of matter too small to be seen. There is an empty space between atoms. Each atom is different in size, weight and shape.
John Dalton adopted Democritus’ theory into the first modern atomic model. Dalton proposed that matter was made up of extremely small, individual particles called atoms. When elements react, it is their atoms that combine to form new compounds.
Further, In the later half of the $19th$ century and in the beginning of the $20th$ century , the research was done by various eminent scientists like J.J. Thomson, Goldstein, Rutherford, Chadwick, Bohr and others established that the atom was not the smallest individual particle but had a complex structure of its own and was made up of still smaller particles like electrons, protons and neutrons.

Note:
The credit for the first atomic theory is usually given to ancient Greeks because Democritus discovered atoms first. A landmark in the progress of chemistry took place with the advent of Dalton’s atomic theory.