Atom Periodic Table Timeline

Democritus propose the idea of the atom. The atom was an indivisible particle that all matter is made of, but the methods to verify it did not exist in that era, so it was not widely adopted for many centuries.

French chemist who, through a conscious revolution, became the father of modern chemistry. Lavoisier demonstrated with careful measurements that transmutation of water to earth was not possible, but that the sediment observed from boiling water came from the container. He burnt phosphorus and sulfur in air, and proved that the products weighed more than he original. Nevertheless, the weight gained was lost from the air. Thus he established the Law of Conservation of Mass.

Antoine Lavoisier discovered that mass is neither created nor destroyed in chemical reactions. In other words, the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction. If we account for all reactants and products in a chemical reaction, the total mass will be the same at any point in time in any closed system. Lavoisier's finding laid the foundation for modern chemistry and revolutionized science.

John Dalton is credited as the father of the modern atomic theory. The theory is composed of five parts. Which includes elements being composed of atoms and that element's atoms are identical in mass.

The theory proposed a number of basic ideas:
All matter is composed of atoms
Atoms cannot be made or destroyed
All atoms of the same element are identical
Different elements have different types of atoms
Chemical reactions occur when atoms are rearranged
Compounds are formed from atoms of the constituent elements

The quantum mechanical model is based on mathematics. Although it is more difficult to understand than the Bohr model, it can be used to explain observations made on complex atoms.

Mendeleev is best known for his work on the periodic table; arranging the 63 known elements into a Periodic Table based on atomic mass, which he published in Principles of Chemistry in 1869. His first Periodic Table was compiled on the basis of arranging the elements in ascending order of atomic weight and grouping them by similarity of properties.

Thomson used a charge-to-mass ratio because he knew the weight of the cathode ray tube, the heat, the electrical current, and how much heat had been added from the electrons firing. He concluded that the negative cathode ray particles were a thousand times tinier than an atom. Along these lines he proved the existence of subatomic particles.

Thomson determined that all matter is made up of tiny particles that are much smaller than atoms. He originally called these particles 'corpuscles,' although they are now called electrons. This discovery upended the prevailing theory that the atom was the smallest fundamental unit.

The plum pudding model, also known as the blueberry muffin model, of the atom by J. J. Thomson, who discovered the electron in 1897, was proposed in 1904 before the discovery of the atomic nucleus in order to add the electron to the atomic model. In this model, the atom is composed of electrons, and surrounded by a soup of positive charge to balance the electrons' negative charges, like negatively charged "raisins" surrounded by positively charged "pudding".