Atomic Theory Steven Petrella Chris Mitchell Andrew Waldron Stephen Caffery

Prevailing Views of Atoms

Democritus -The first person to start developing an idea of atoms came around 460 B.C. -The Greek philosopher Democritus started wondering into how many pieces you could break into matter -He used the word atomos which means “uncuttable” in Greek.

Why didn’t people start accepting this new idea? Aristotle dismissed the atom idea so people followed Aristotle’s thought and did not explore it more. People could obviously not see atom so that led to doubts. Democritus’s view of an atom was more philosophical and he did not have physical evidence.

Other Views of Atoms Paul of Taranto in the 13 th century developed the idea of corpuscularianism which said everything possessed an inner and outer layer of minute particles. Corpuscularianism became the dominant thought of the time In 1661 Robert Boyle brought up again that matter was composed of a combination of different atoms instead of the classical elements of air, fire, earth, and water

Discovery of Atom

Lavoisier & Dalton Antoine Lavoisier (1789) – Discovered Law of conservation of mass – Defined an element as something that cannot be broken down any further using chemistry John Dalton (1805) – Proposed that each element consists of atoms joined together to form a chemical compound – Original theorist of modern atomic theory

More on Dalton Dalton did not give a size for the atoms, but everyone just assumed small In 1805, published a paper presenting his list of relative atomic weights

Dalton’s atomic theory Elements can be distinguished by their respective relative atomic weights All elements’ atoms are identical Atoms can combine together to form new compounds and will always have the same relative number of atoms Atoms cannot be created or destroyed All elements are made up of atoms

Impacts on Society and Science

Results of finding atoms Scientists now began looking even smaller inside atoms Plum Pudding Model – J.J. Thomson in 1897 discovered the electron – He stated that every atom had an electron and changed the belief of the atom – He created the plum pudding model that electrons rotate in rings inside of the atom.

New ways to organize matter The discovery of the atom led to improved ways to organize matter Periodic Table – Gave us a way to classify and sort elements by size, mass, and atomic number. – Has a pattern for electronegativity, polarity, ionization energy. – Allows the basis for modern chemistry and the understanding of how elements combine to make things we use in our everyday lives.

More modern uses of atoms Particle Acceleration Atom splitting

Particle Acceleration Used to create antimatter which is fundamental in studying the origins of the Universe. Expected to answer some fundamental questions of physics and allow humans to further understand laws of nature. Product of particle acceleration is the collision of atoms. Apparatus used to create atom collisions is called the Large Hadron Collider, or LHC, which was invented by scientists near Geneva, Switzerland.

Atom Splitting A.k.a Nuclear Fission Can be used to create nuclear power which can be used for things like power or bombs utilized by militaries around the world.

Works cited