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atomic model, in physics, a model used to describe the structure and makeup of an atom. Atomic models have gone through many changes over time, evolving as necessary to fit experimental data. For a more in-depth discussion of the history of atomic models, see atom: development of atomic theory.
Learn about the history and postulates of Dalton's atomic theory, the discovery of the electron, and the atomic model. Explore the concepts of matter, elements, compounds, and chemical reactions with examples and diagrams.
26 sie 2020 · The modern atomic theory, proposed about 1803 by the English chemist John Dalton (Figure \(\PageIndex{4}\)), is a fundamental concept that states that all elements are composed of atoms. Previously, an atom was defined as the smallest part of an element that maintains the identity of that element.
One of the greatest accomplishments was the development of the quantum mechanical model. Chapter 5 traces the discoveries that led to the model and the describes the relationship between the electronic structure of atoms and the properties of elements.
Schrödinger's wave model for hydrogen replaced Bohr's model, with its neat, clearly defined circular orbits. The modern model of the atom describes the positions of electrons in an atom in terms of probabilities.
Bohr's model suggests that the atomic spectra of atoms is produced by electrons gaining energy from some source, jumping up to a higher energy level, then immediately dropping back to a lower energy level and emitting the energy difference between the two energy levels. The existence of the atomic spectra supports Bohr's model.
In this explainer, we will learn how to describe the concepts of modern atomic theory. Each successive model of the atom was developed to produce a theoretical explanation for a practical result. John Dalton’s hard-sphere model accounted for the way atoms pack together.
