Background Information

Background Information

An atom is the smallest unit of ordinary matter that forms chemical elements. It is composed of a dense central core and a surrounding cloud of energy, containing electrons. Electrons are determined by their stability and behaviors. Over the course of earths life many intelligent people found parts of what is disocvered to be the offical aceepted model of an atom used in everyday life. From the fifth century BCE to 1926, there has been various accounted models from various great minds. Some of the intelligent minds include Democritius, Dalton, Thompson and more. As for the models included in time: Solid Sphere, nuclear, planetary, etc. Over the course of time for discovery of the atom, it held many different beleifs and ideas on what was 'wrong' and 'right'

Significance

People

Models

History of the discovery of an atom

Solid Sphere

Quantum

Nuclear

Neils Bohr

J.J Thompson

1913

1897

1926

1909

1803

Ernest Rutheford

Erwin Schrodinger

John Dalton

Plum Pudding

Planetary

How the discovery plays a bigger role

How this helps the world

The discovery of an atom led to the foundation of modern chemistry. Implications: - Understanding of energy - nuclear energy Impact: - Creation of compounds -Properities of elements - Atomic theory (Sciengist, 2023)

• Science studies
• Technology (MRI and x-ray)
• Medicines
• Conductors
• Research
• Batteries
• Computer Chips

(Sciengist, 2023)

References

Clifton, J. (2021, July 7). A Level Chemistry Revision: Physical Chemistry- Atomic structure. Reagent. https://www.chemicals.co.uk/blog/a-level-chemistry-revision-physical-chemistry-atomic-structure?ref=fabioxie.com Helmenstine, A. M. (2025, June 9). A Brief History of Atomic Theory - Chemistry. ThoughtCo. Retrieved April 23, 2026, from https://www.thoughtco.com/history-of-atomic-theory-4129185 Hird, S. (2026, February 25). History of the atom - GCSE Chemistry Revision Notes. Save My Exams. Retrieved April 23, 2026, from https://www.savemyexams.com/gcse/chemistry/aqa/18/revision-notes/1-atomic-structure-and-the-periodic-table/1-1-simple-model-of-the-atom/1-1-6-history-of-the-atom/ John Dalton & The Theory of Atomism. (n.d.). Science History Institute. Retrieved April 23, 2026, from https://www.sciencehistory.org/education/scientific-biographies/john-dalton/ Niels Bohr – Biographical - NobelPrize.org. (n.d.). Nobel Prize. Retrieved April 23, 2026, from https://www.nobelprize.org/prizes/physics/1922/bohr/biographical/ The Nobel Prize. (n.d.). Ernest Rutherford. The Nobel Prize. https://www.nobelprize.org/prizes/chemistry/1908/rutherford/biographical/ The Nobel Prize. (n.d.). J.J Thomson. The Nobel Prize. https://www.nobelprize.org/prizes/physics/1906/thomson/biographical/ Schrödinger and the Wave-Mechanical Model of the Atom. (n.d.). The Physics Classroom. Retrieved April 23, 2026, from https://www.physicsclassroom.com/Chemistry-Tutorial/Modern-Atomic-Model/Schrodinger-and-the-Wave-Mechanical-Model Science for Everybody. (2025). The History of the Atom. https://scienceforeverybody.com/chemistry/atomic-structure-and-the-periodic-table-contents/the-history-of-the-atom/ Sciengist. (2023). The Discovery of the atom: The foundation of modern chemistry. https://sciengist.com/the-discovery-of-the-atom-the-foundation-of-modern-chemistry/

J.J Thomson lived in Manchester, going through college making a name for himself. Eventually becoming a lecturer. The earliest intrest that led him to the atomic science was based on Treatise on the Motion of Vortex Rings. Thomson went to America to give lectures and came home with great ideas that ended up as his discovery of the electron. Calling it "Plum puding model." (The Nobel prize, n/a)Thomson discovered: - Atoms are spheres of positive charge - Electrons are embedded inside like plums in a pudding ( Science for Everybody, 2025)

John Dalton was a techer and public lecture person. After his move to Manchester, he was introduced to philisophical science and literary. The start of his infatuation for atoms started with meterological. Further basing observations from other scientist laws. (Science History Institute, 2026)John Dlaton proposed: - All matter is made of tiny particles called atoms- Atoms are solid spheres-Different elements contain different types of atoms( Science for Everybody, 2025)

Bohr was born in Copenhagen in 1885. He grew up in a family full of intelligent people. In 1912, he worked in Ruthefords laboratory that allowed him to publish his ideas and findings of the atom based on Plancks Theory and Heisenburg's ideas. (The Noble Prize, n/a) Bohrs findings: - Electrons orbit the nucleus at fixed energy levels called shells - The shells prevent electrons from spiralling into the nucleus (Science For everybody, 2025)

Rutheford was born in New Zealand . Went to Government schools and eventually college for physical science. Rutheford was a student of Thomson's. Eventually leading to his expierement of the gold foil sheet. (The Nobel Prize, n/a). Ruthefords findings;- Atoms are mosly empty space- Small dense positvaley charged nucleus- electrons orbit the nucleus( Science for Everybody, 2025)

Schrodinger was born in Vienna, in 1887. His family was surrounded in various aspects of academics. Erwin was intrested in various aspects of life as well. He taught at many schools himself all over, giving him expierence. In addition to liking physics he came up with the wave equation that allowed him to introduce against Bohrs model and assumptions. (The Nobel Prize, n/a)Schrodinger findings: -Electrons are found within orbitals, not on a set orbital - Eelctron clouds where the electron may possibly be found. (The Physics Classroom, n/a)

The discovery of the atom was not a single moment, but a multi-generational transition from abstract philosphy to rigorous expierements. To map the atom, the greatest minds in scientific history had to master the art of indirect observation. Due to the building blocks of the universe remaining hidden from the naked eye. The discovery of the atom required a unique brand of intellectual creativity. The earliest intelectural being Democritius from fith centruy BCE in regard to a philosphpical concept. It wasn't until the eighteenth century for more scientifc intellectuals to provide more scientific evidence for the atom. John Dalton was to become of the solid sphere basing off of the Law of Conservation of Mass and definitive proportions that allowed him to come to his conclusoins. However, furthe rinto the eighteenth century, J.J. Thompson discovered the electron with the pressence of atoms having a negative charge. Furthermore, Ernest Rutheford, a student of Thompson discovered the nucleus held most of the mass. Nect came Neil Bohr, exploring why and how electrons orbit the nucleus. As time went on many others found multiple discovered that led to the bigger and fully accpted model of an atom. (Helmenstine, Anne. 2025)

The transition from a theoretical idea to a complex physical model was driven by five disticnt types of discoveries: the identifictaion of a solid mass, electrons, mass of atom, direction and set place alonside the path of electrons. The identification of the simple solid sphere where all matter is made of tiny particle, they are solid spheres and contain different types. In 1897 the discovery of the elctron, proposing the electron plum pudding model where electrons are spheres of positive charge and electrons are embeded inside like pudding. Ernest Rutheford, whom was Thompsons student (Helmenstine, Anne. 2025) carried out the gold foil expierement with alpha particles. The findings concluded of the firing positvely charged alpha particles at a thin gold foil, most passed through and some were bounced back. Eventually leading to the statements of atoms are mostly empty space with a small, dense positvely charged nuclues with electrons orbiting the nucleus. Leading to the nuclear model, Neil Bohr improved Ruthefords by stating that electrons orbit the nucleus at fixed energy levels (shells). These shells of energy levels prevent electrons from spiralling into the nucleus. (The History of the Atom, 2025). Coming to 1926, the most recent accpted model of the atom, Erwin Schrodinger states electrons do not move in set paths around the nuclus, but in waves, thus called the quantum mechanical wave model. The location of the electrons are defined as 'clouds of probability' called orbitals. where the electrons are likely to be found. (Clifton, 2021).

The history of the discovery of the atom isn't just a time line of old scientist in labs; it represents the ultimate shift in how humnaity percieves reality. It's the story of how we moved from veiwing the world as a collection of things to understand it as a complex ideologies. For centuries the atom was more philisophical toy. The history of the atom marks the birth of scientific method. Showing transition from thinking something might be true to, being able to prove something was true with measureable ways. The intelligent minds through time helped: Dalton, Thomson, Rutheford, Bohr and Schrodinger.The modern world relies on the atomic code. Understanding how electrons more and jump between energy levels. Electronics, medicine and role in everyday life. By discovering the structure of an atom, we finally understand as scientist why elements react the way they do. Allowing us to create synthetic and multiple types of materials. The history of the atom is sort of like peeling an onion. Everytime we thought we found the smallest part, we found something smaller and more energetic inside.