Atomic Structure and Historical Development of Atomic Structure

July 21, 2025

Atom

is the smallest unit of matter that retains all the chemical properties of an element.

Atomos

Greek word that means Indivisible, because it was once thought that atoms cannot be divided into smaller particles.

Protons, Neutrons, and Electrons

Atoms are made up of three tiny kinds of particle.

500 B.C

year where Leucippus and Democritus proposed the Idea of Atom as the smallest particle of matter.

Leucippus and Democritus

they proposed the Idea of atom as the smallest particle of matter.

The Idea of atom as the smallest particle of matter.

Around 500 BC, Leucippus and Democritus proposed what?

Year 1777

year where Antoine Lavoisier proposed the law of Conservation of Mass.

Antoine Lavoisier

he proposed the law of Conservation of Mass

proposed the law of Conservation of Mass

In the year 1777, Antoine Lavoisier proposed what?

Law of Conservation of Mass

states that in a closed system, mass is neither created nor destroyed during a chemical reaction, this principle means that the total mass of the reactants equals the total mass of the products.

Year 1794

year where Joseph Louis Proust proposed the Law of Definite Composition.

Joseph Louis Proust

He proposed the Law of Definite Composition.

Proposed the Law of Definite Composition.

Joseph Louis Proust proposed what?

Law of Definite Composition is also known as

Law of Constant Composition

Law of Definite Composition

states that a chemical compound always contains the same proportion of elements by mass, regardless of the amount of the compound or its source.

Year 1803

year when John Dalton proposed the Law of Multiple Proportions

John Dalton

He proposed the Law of Multiple Proportions

proposed the Law of Multiple Proportions

In 1803, John Dalton proposed what?