An atom is the smallest unit of matter that has properties of a chemical element. It is made up of Protons, Electrons, and Neutrons. Atomic Theory states that matter is made up of discrete or very tiny particles known as an atom.

The Theory began in 5^th century BC, with discoveries from Democritus, a philosopher from Ancient Greek who described atom as an indivisible unit. In 1897, the British scientist J.J Thomson also discovered that molecules are made up of tiny particles. (Benedek, and Jan, 10)It was until in 1803 that John Dalton an English Chemist reviewed old theories and came up with more hard evidence and answers for solving many questions about atoms through some experiments. He said that matter could not be divided. His discoveries were not confirmed until in the 19^thcentury.

During Democritus time, there was no technology thus he did not perform any experiment to support his discovery, in (1766-1844) John Dalton experimented to support the existence of an atom. He also explained the ability of water to absorb gases for example carbon (iv)oxide is more absorbed than nitrogen gas due to its high mass density and it’s also larger than nitrogen gas. He also described matter using the law of conservation using both closed and open systems and concluded that matter could not be created or destroyed.

Dalton also added that all atoms of an identical element have the same mass and differs from one atom to another. When a chemical reaction occurs, it leads to rearrangement of atoms. Compounds are formed when different atoms combine in a fixed ratio. Chemical and physical properties of atoms of the same element together with mass and size are the same and different from other atoms of the various aspects.

Work Cited

Benedek, Giorgio, and Jan Peter Toennies. Atomic-Scale Dynamics at Surfaces: Theory and Experimental Studies with Helium Atom Scattering. Vol. 63. Springer, 2018.

Do you need high quality Custom Essay Writing Services?