The terms theory and model are defined, and students learn how a theory remains valid. Atomic Theory: The Development of the Atomic Theory: The terms theory and model are defined, and students learn ...

The Bohr model, introduced by Danish physicist Niels Bohr in 1913, was a key step on the journey to understand atoms. Ancient Greek thinkers already believed that matter was composed of tiny basic ...

There are multiple ways to create two- and three-dimensional models of atoms and molecules. With the advent of cutting-edge apparatus that can image samples at the atomic scale, scientists found that ...