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Aristotle
Aristotle was a Greek philosopher who lived from 348 BC to 322 BC. He believed that the universe was made up of four elements: earth, air, fire and water. Each of these elements had its place depending on its heaviness. Although his theory was not aimed to contribute to the atomic theory, His idea is what began and led on to the ongoing discovery and extension of the atomic theory. -
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Democritus
Democritus is a famous Greek philosopher and scientist. He lived from 470 to 380 B.C. He was the man who came up with the theory of Atoms. This discovery changed our view of the atom as he made the concept of an atom, before this the particles that everything was made up of had no name. He believed that all matter is made up of miniscule particles. He called these particles Atoms. -
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Kanada
Kanda was an Indian Philosopher who lived during 600 BCE. He founded the Vaisheshika school of philosophical thought. Their contribution to the atomic theory was that they proposed that matter is made up of atoms that are indivisible and eternal, that each atom had its own unique individuality and that atoms make up the four elements, water, fire, earth and air. They had various theories about how these atoms combine and they believed that this was caused by the will of Ishvara, a Hindu God. Al -
Isaac Newton
Isaac Newton is an English Physicist and Mathematician who lived from 1642 to 1727. His contribution to the atomic theory was that he proposed a mechanical universe where all small solid masses were in motion, so he believed that there were tiny pieces if mass that were swimming everywhere. The significance of his contribution is that we began to understand that atoms or particles move and are not stationary. -
Antoine Lavoisier
Antoine Lavoisier also known as the Father of Modern Chemistry lived from 1743 to 1794. His contribution to the atomic theory was that he discovered water is made up of hydrogen and oxygen. Lavoisier also invented the analytical balance and created the law of conservation of mass which showed that chemical elements were neither created nor destroyed, they are just combined into different compounds in chemical reactions. Additionally he created the metric system and wrote the first extensive list -
John Dalton
John Dalton was an English Chemist who lived from 1766 to 1844. His contribution to the Atomic Theory was that he had a theory that atoms were just solid spheres that came together to build things. He tried his theory by using spheres and stick and connecting them together. He also help extend our knowledge about the Atomic theory, his theory was that 1. All matter is made up of atoms. Atoms are indivisible and indestructible2. All atoms of a given element are identical in mass and properties. -
Michael Faraday
Michael Faraday was an Irish Chemist who lived from 1791 to 1867. His contribution was not intended for the atomic theory but G.J. Stoney noticed the significance of it. This was that he studied the affect of electricity on solutions and created the term electrolysis which is the process in which a chemical is broken down using an electrical current. -
Julius Plucker
Julius Plucker is a German mathematician, physicist, and chemist who lived from 1801 to 1868. His contribution to the atomic theory is his identification and experiment with what he named cathode rays. Cathode rays are a beam of electrons released from a cathode of a high vacuum tube. Thomson later reinterpreted Pluckers work with his own discovery of electrons. -
G.J.Stoney
George Johnstone Stoney was an Irish scientist who lived from 1826 to 1911. His contribution to the atomic theory was that he proposed that electricity was made up of separate negative particles called electrons and he created the name electron. This further developed our knowledge on the atomic theory as naming the electron this is a vital part in the atom. -
Dimitri Mendeleev
Dimitri Mendeleev was a Siberian Chemist and inventor who lived from 1834 to 1907. He contributed greatly to the atomic theory through his discoveries about elements. He drew a table outlining various elements arranged into 7 groups of similar properties. They were arranged according to weight and each element was given a symbol. It consisted of 63 elements, none of the Nobel gases as they had not yet been discovered. This is now known as the Periodic Table. Mendeleevs advances concerning elemen -
J.J.Thomson
Joseph John Thomson who lived from 1856 to 1897, was a physicist who discovered the electron. The electron is the negatively charged part of every atom. His contribution to the Atomic theory was the discovery of the electron and the plum pudding theory which is now not relevant today. He also came up with the plum pudding model theory as and example of how an atom works. This was where the pudding positively charged the plums, the plums were dotted through the dough as the negatively charge elec -
Ernest Rutherford
Rutherford was a New Zealand Chemist who lived from 1871 to 1937. Rutherford’s contribution to the atomic theory was that he proposed that most of the mass of an atom was contained in the nucleus, which is in the centre, and the rest of the atom was mostly empty space. He discovered this after the results of his famous gold foil experiment. He found that the majority of particles passed straight through the foil and approximately 1 in 8000 deflected back to him, which lead him to the theory that -
Niels Bohr
Bohr who lived from 1885 to 1962 and originated from Denmark is most well known for his contribution to the atomic theory in his atomic model which was extended and based on the one created by his mentor Rutherford. Bohr proposed that electrons travel only in certain successively larger orbits. He suggested that the outer orbits could hold more electrons that the inner ones and this allowed them to determine the atoms chemical composition. For his work he was awarded the Nobel Prize in 1922. He -
Erwin Schrödinger
Erwin Schrödinger is an Austrian physicist who lived from 1887 to 1961. His contribution to the atomic theory was that he took the Bohr atom model a step further. He developed mathematical equations that described the movement of an atom. It is known as the quantum mechanical model of the atom. It does not define the exact path of the electron but predicts the location of the electron. It can be drawn as a nucleus surrounded by an electron cloud, where the cloud is most dense there is a higher c -
James Chadwick
James Chadwick born in England who lived from 1891 to 1974 made the significant discovery and proof of the existence of Neutrons which is a elementary particle without any electrical charge and a core part of the atoms nucleus. It was one of the most important scientific discoveries of the twentieth century which solved the puzzle of the atom. For this breakthrough Chadwick was awarded the Nobel Prize for Physics. Thanks to Chadwick’s discovery our knowledge of the atom was enlarged and this led
