Hi my name is Democritus. It is 400 BC and my theory is that everything around is made of tiny particles called Atom.
My name is John Dalton. It is the year 1808 and I propose that all matter is made up of atoms and those atoms are indivisble and cannot be destroyed.
My name is Dmitri Mendeleev and it is currently the year 1869 and I have created the periodic table with 63 elements.
Democritus was the beginning of the atom theories in 460 BC. He was the first person who proposed that all matter was made up of tiny units called atoms. He didn't do experiments neither was he able to do them due to the lack of technology and equipment.
John Dalton based his theory on the law of conservation of mass and the law of constant composition. It had 4 parts which state;All types of matter are made up of atoms, which are indivisible All atoms of a given element are identical in mass or propertiesCompounds are combinations of two or more different types of atomsA chemical reaction is the rearrangement of atoms
Dmitri Mendeleev created the periodic table. he created it using the Mendeleev Theory. The theory was arranging the 63 elements based on their atomic mass.