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400 BCE
The Greeks- Democritus
In 5th century B.C, Greek philosopher and scientist Democritus was known famously for his work with atomic theory and the first iteration of the atomic model. The Greeks had come to the conclusion that everything could only be cut so short thus, everything was made up of particles of itself. For example, water molecules were made up of tiny particles of water, Iron was made up of particles of iron. They named these particles, atoms; derived from the Greek word atomos; meaning Indivisible. -
Christiaan Huygens- (1629-1695)
Christiaan Huygens had made contributions to the atomic model. Huygens was famously known for his work in dynamics, the study if forces on different bodies and how they acted upon them. He also founded the true shape of Saturn's rings and the wave theory of light. His contribution to the atomic model, was how different forces such as gravity acted on atoms. -
Isaac Newton- (1643-1727)
Isaac Newton is known famously for his 3 laws of motion. Newton had made a contribution to atomic theory. His work with atomic theory was that he suggested that the particles in the atom were in motion and they were non-stationary. -
John Dalton- (1766-1844)
John Dalton, an English chemist, physicist, and meteorologist; had discovered that molecules are not particles of themselves, but rather everything is made up of atoms. Dalton suggests that atoms are indivisible and indestructible. This model of the atom was conceptualized to be a spherical shape of particles which make up different molecules. Dalton had come to the conclusion that a water molecule was made up of one atom of hydrogen and one atom of oxygen. -
Gustav Kirchhoff- (1824-1887)
Gustav Kirchoff was a mathematician who studied electricity and created Kirchoff's laws. His work in chemistry had helped contribute to atomic theory. Kirchoff along with Robert Bunsen had created the field of Spectroscopy. This field will split the light into different wavelengths , which determines an elements chemical composition -
James Maxwell- (1831-1879)
James Maxwell, known best for his work in electromagnetism, contributed to the theory of the atomic model. Maxwell had contribute to the atomic model by discovering that there was a connection between light and electromagnetism, coming to the conclusion that there could be electromagnetic waves. -
Heinrich Hertz- (1857-1894)
Heinrich Hertz, a German physicist who was the first to successfully conclude Maxwell's theory, used this work to contribute to atomic theory. Hertz had tested Maxwell's theory of electromagnetic waves and concluded his theory to be true. -
JJ Thomson- (1856-1940)
JJ Thomson had made an important contribution to atomic theory. Thomson had discovered the electron. He tested different gasses in a glass tube attached with negatively charged cathodes. Because of this discovery, he had concluded that the atom is a positively charged cloud, with negatively charged particles in the centre of it (Aka. The Plum Pudding Model) -
Max Planck- (1858-1947)
Max Planck's most famous work, was in deriving the relationship between energy and the frequency of radiation, stating that energy released from a resonator could only take on quanta. He came to this conclusion by observing wavelength distributio-ns from a black body -
Albert Einstein- (1879-1955)
Albert Einstein, known famously for his work in both general and special relativity. Einstein had contributed to the atomic theory by discovering the basis of the release of atomic energy, meaning that energy and matter were exchangeable. -
Ernest Rutherford- (1871-1937)
Ernest Rutherford had discovered that there aren't only electrons, but there are positively charged particles as well. Rutherford had decided to test the theory of the plum pudding model and shot alpha particles at a piece of gold foil. Rutherford thought that if every particle was negatively charged, the particles should go straight through the foil. During experimentation, most of the particles shot through, but some were deflected from large angles. He concluded that atoms must have a center -
Niels Bohr- (1885-1962)
Neils Bohr contributed to atomic theory by critiquing Rutherford's model. Bohr suggested that the planetary model of the atom was wrong. He suggested that the electrons would eventually collapse into the nucleus. Instead, Bohr concluded that the electrons orbit around the nucleus in certain orbits. -
Erwin Schrödinger- (1887-1961)
Erwin Schrödinger has made one of the most significant contributions of modern chemistry. He suggested that electrons weren't particles following a specific orbit but rather behaved like waves. He came up with the idea that electrons couldn't be in an exact spot with the atom, but they could pinpoint their location based on probabiltiy. This idea was expressed with electron orbitals. These orbitals could hold a certain amount of electrons, and some had different amounts of orientations.
