-
400 BCE
Aristotle
-Greek Philosopher
-believed that everything was made up of water, Earth, fire, and air -
400 BCE
Democritus
-Greek philosopher
-found and created the idea/principle of an atom
-created a theory that atoms are sold and undestroyable things and move in empty space until stopped
-the properties were affected by the shape and size of the atom itself -
427
Plato
-Philosopher
-created a theory where geometric shapes such as cubes, octahedrons, and more were used to represent elements, as the base of his model was that atoms were triangles
-ex: water=icosahedron -
Alchemist
- believed in both science and mystics/magic -believed that sulfur and mercury make up all metals
-
Antoine Lavoisier
-Chemist
-described the law of conservation
-clarified that matter is made up of atoms that are not destroyed, created, or effected during a chemical reaction -
John Dalton
-Chemist
-Created atomic theory as we know it- all matter is made of atoms that cannot be destroyed -
Newland's law of Octaves
-Classification of elements by atomic weight from smallest to biggest
-Similar physical and chemical properties occur every 7 elements
-Created by chemist J.A.R. Newlands -
Mendeleev's Pd table
Created by chemist—Dmitri Mendeleev
-created an orderly table of the elements based on atomic weight from least to greatest -
Photoelectric effect
-Discovered by physicist Heinrich Rudolf Hertz
-when a material releases an electronically charged particle in a it takes in radiation -
Discovery of radioactivity
-discovered by Henri Becquerel
-Becquerel discovered radioactivity by a photographic plate that was covered by black paper turning black by uranium salts even though the paper was covering it while being processed -
Charge of the electron
discovered by J.J. Thomson
-found electrons while experimenting with cathode rays -
Discovery of the electron
-Discovered by J.J. Thomson
-During an experiment involving cathode ray tubes, Thomson discovered electrons by showing that those rays were charged negatively and that the gas surrounding it was positive. This sparked his idea for the plum pudding analogy/model.
-This discovery helped share the idea that an atom's structure wasn't as simple as they thought and that it is more complicated. -
Planck's quantum theory of light
-created by physicist Max Planck
-only certain amounts of energy can be taken in or come out of and atom or molecule -
Plum Pudding Model
-Created by J.J. Thomson
-model thar showed the discovery of the electron
-Called the plum pudding model because the electrons representing the "plums" are sat around a positively charged volume which represents the "pudding" -
Robert Millkian
-physicist
-discovered the charge that an electron charge using an oil drop experiment -
Rutherford's gold foil experiment
-created by Ernst Rutherford
-positively charged alpha particles hit gold foil and showcased that the atoms of gold foil are full of empty space -
Bohr's Planetary Model
-proposed a theory through a model which was later used to use/support quantam theory
-electrons can only be in orbit of certain ones not all
-similar look of planets in orbit
-Created by physicist Niels Bohr -
Mosley's atomic numbers
-created by physicist Henry Mosley
-states that the atomic number is the same number of protons in an element
-created during an experiment of recording the frequencies of xray spectura of different elements -
Discovery of proton
-Discovered protons through an experiment when a nuclear reaction occurred in an atom
- Discovered by physicist Ernst Ruthorford -
Shrodinger Equation
-created by physicist Erwin Shrodinger
-describes the function of the wave that control the movement of a small particle and how they are influenced by outside factors -
Heisenberg Uncertainty Principle
-created by physicist Laureate Werner Heisenberg
-the principle states that there is no exact way to calculate the speed of a particle in an atom with accuracy to a tea, therefore there is an uncertainty in what it is or will ever be -
Discovery of the neutron
-discovered by physicist James Chadwick
-During an experiment with many types of elements such as lithium and beryllium, he discovered alpha particles clashing with the atoms of these elements
-He curated this experiment with a vacuum pump and polonium source which created a type of radiation