John Dalton
Event HeadlineR.V:John Dalton was an English scientist, chemist, physicist and meteorologist.He was born on the 6 September 1766 at Eaglesfield, near Cocker mouth in Cumberland and died on the 27 July 1844.He was best known for his pioneering work in the development of the modern atomic theory and In 1803, his own theory of “atoms” that were the basis of all matter.
John Dalton theory was based on Democritus and other Ancient Greek philosophers theories.john daltons has five main points of his theory which are: 1. Elements are made of tiny particles called atoms. 2. The reason elements are different from one another is that the atoms are different from one another; in particular, they have different masses. 3. An element is pure because all atoms of an element were identical in size, mass and other properties. 4. Compounds are made of atoms of different elements bonded together somehow, perhaps by hooks, and are not easily separated from one another. The elements in compounds are always in simple, whole number ratios, like 1:1 or 1:2 (the Law of Definite Proportions) 5. Atoms cannot be created, divided into smaller particles, nor destroyed by chemical processes; a chemical reaction just changes the way atoms are grouped together (the Law of Mass Conservation). Democritus and other Ancient Greek philosophers had come up with the basic idea of atoms.Dalton's theory was a more developed theory to the Ancient Greek philosophers and was different due to it was based on careful chemical measurements and experimentation.Scientists of this time accepted Dalton’s ideas as his theory clearly explained their own observations. |
M.F:He applied Newton's idea of small, indivisible atoms to the study of gases in the atmosphere and used it to advance a quantitative explanation of chemical composition.
Experiments with gases that first became possible at the turn of the nineteenth century led John Dalton in 1803 to propose a modern theory of the atom based on the following assumptions. 1. Matter is made up of atoms that are indivisible and indestructible. 2. All atoms of an element are identical. 3. Atoms of different elements have different weights and different chemical properties. 4. Atoms of different elements combine in simple whole numbers to form compounds. 5. Atoms cannot be created or destroyed. When a compound decomposes, the atoms are recovered unchanged. |