Atoms and Molecules

Ancient Indian and Greek thinkers proposed

Ancient Indian and Greek thinkers proposed that matter can be divided into smaller and smaller particles until a stage is reached beyond which further

In a chemical reaction

In a chemical reaction, the total mass of reactants is equal to the total mass of products. Lavoisier established this using careful balance-based exp

A pure compound always contains

A pure compound always contains the same elements combined in the same proportion by mass, no matter where it is obtained from or how it is prepared.

Dalton arranged earlier atomic ideas into

Dalton arranged earlier atomic ideas into a theory in 1803. He stated that matter consists of atoms, atoms of the same element are identical, atoms of

When two elements form more than

When two elements form more than one compound, the masses of one element that combine with a fixed mass of the other are in simple whole-number ratios