Difference Between Democritus and Dalton Atomic Theory

The key difference between Democritus and Dalton atomic theory is that the Democritus atomic theory is an ancient theory that scientists later refined and elaborated whereas Dalton atomic theory is a comparatively modern, scientific theory that we cannot discard due its important statements.

Atomic theory is the scientific theory that describes the nature of matter by means of discrete units called atoms. The origin of this theory is from ancient Greece, which then entered the scientific mainstream. The word “atom” means “uncuttable” in Greek terms.

CONTENTS

1. Overview and Key Difference
2. What is Democritus Atomic Theory
3. What is Dalton Atomic Theory
4. Side by Side Comparison – Democritus vs Dalton Atomic Theory in Tabular Form
5. Summary

What is Democritus Atomic Theory?

Democritus atomic theory is the ancient theory that describes the nature of matter in terms of atoms. According to Democritus (99-55 BC), atoms are infinite in number and eternal.

We cannot create them, and the composition of atoms in a substance determines the qualities of that substance. However, this theory was refined and elaborated later by the Greek philosopher Epicurus (341 – 270 BC).

What is Dalton Atomic Theory?

Dalton atomic theory is a modern scientific theory that describes the nature of matter in terms of atoms. With the development of the law of conservation of mass and the law of definite proportions, John Dalton developed a new idea as the law of multiple proportions. It states that if the same two elements can be combined to form a number of different compounds, then the ratios of the masses of the two elements in their various compounds will be represented by small whole numbers.

Thereafter, he developed the Dalton atomic theory which has the following statements.

1. Each chemical element contains extremely small particles that are invisible to the naked eye; atoms.
2. We cannot either create or destroy atoms.
3. All atoms of the same chemical element are equal in mass and other properties.
4. When forming a compound, different elements combine in different but simple numerical ratios.

However, this atomic theory is not correct at all circumstances. For example, the second statement is incorrect because we can divide an atom into subatomic particles via nuclear fission. The third statement becomes incorrect because there are isotopes; atoms of the same chemical element that are different from each other according to atomic masses. However, we cannot use these incorrect points to completely discard this theory because it can correctly explain the law of conservation of mass and the law of constant composition; if all the atoms of an element are alike in mass and if atoms unite in fixed numerical ratios, the percent composition of a compound must have a unique value without regards to the sample analyzed.

What is the Difference Between Democritus and Dalton Atomic Theory?

Democritus atomic theory is the ancient theory that describes the nature of matter in terms of atoms whereas Dalton atomic theory is a modern scientific theory that describes the nature of matter in terms of atoms. A significant difference between Democritus and Dalton atomic theory is that according to the Democritus atomic theory, the atoms are infinite in number, uncreated, and eternal, and that the qualities of an object result from the kind of atoms that compose it. Whereas, the Dalton atomic theory describes that atoms are invisible to the naked eye, we cannot either create or destroy them, all atoms of the same chemical elements are equal and compound forms from the combination of different chemical elements in simple ratios.

However, they mainly differ according to the current usage of the theory; therefore, the key difference between Democritus and Dalton atomic theory is that Democritus atomic theory is an ancient theory that scientists later refined and elaborated whereas Dalton atomic theory is a comparatively modern, scientific theory that we cannot discard due its important statements.

The below infographic on the difference between Democritus and Dalton atomic theory describes all the possible differences between both the theories.

Summary – Democritus vs Dalton Atomic Theory

The two atomic theories, Democritus atomic theory and Dalton atomic theory, differ from each other according to their current usage. Therefore, the major difference between Democritus and Dalton atomic theory is that the Democritus atomic theory is an ancient theory which scientists later refined and elaborated whereas the Dalton atomic theory is a comparatively modern, scientific theory that we cannot discard due its important statements.

Reference:

1. “Atomic Theory.” Wikipedia, Wikimedia Foundation, 30 Sept. 2018. Available here 
2. Libretexts. “Atomic Theory.” Chemistry LibreTexts, Libretexts, 24 Aug. 2017. Available here

Image Courtesy:

1.”Democritus”By Firkin at Openclipart – Openclipart, (CC0) via Commons Wikimedia
2.”Combustion reaction of methane”By JyntoRobert A (CC BY-SA 3.0) via Commons Wikimedia