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500 BCE
The alchemist
invinted experimental techniques and laboratory tools such as funnels flasks and cuppets. -
428 BCE
Plato
he found that there are only five solid shapes whose sides are made from regular polygons such as triangles, squares, pentagons, hexagons and cubes. -
400 BCE
Democritus
He developed the concept of the 'atom he came up the with the word atom meaning indivisible in Greek. -
330 BCE
Aristotle
invented the field of formal logic and he identified the various scientific disciplines and explored their relationships to each other. He was also said to be a teacher. -
330 BCE
solar system model
Rutherford model, also called Rutherford atomic model, nuclear atom, or planetary model of the atom -
Robert Boyle
discovered that the volume of a gas decreases with increasing pressure -
Lavoisier
determined that oxygen was a key substance in combustion, and he gave the element its name -
Jhon dalton
he total pressure of a mixture of gases amounted to the sum of the partial pressures that each individual gas exerted while occupying the same space. -
Solid sphere of Billiard Ball model
an atomic model proposed by John Dalton in 1803 stating that all objects are made of particles called atoms, and that they are solid spheres that cannot be divided further into smaller particles -
Dmitri Mendeleev
also developed the periodic classification of the elements hhe also found that when all the known chemical elements were arranged in order of increasing atomic weight the resulting table displayed a recurring pattern or periodicity of properties within groups of elements. -
Photoelectric effect
when a monochromatic light shines on a metal plane, electrons are released due to the metal plate's photoelectric effect -
J.J. Thomson
showed that all atoms contain tiny negatively charged subatomic particles or electrons -
Earnest Rutherford
Came up with the gold foil experiment and found that the experiment showed that the atom consists of a small, massive, positively charged nucleus with the negatively charged electrons being at a great distance from the center. -
Plancks Quantum theory of 1
the energy of light is proportional to the frequency, and the constant that relates them is known as Planck's constant (h -
the curies
discovered polonium and radium also discovered that the atoms remained constant, no matter the condition or form of the uranium -
plum plumming model
J.J. Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons -
Robert Millikan
discovered the elementary charge of an electron using the oil-drop experiment. -
Henry G.J. Mosely
discovered the atomic number of each element using x-rays, which led to more accurate organization of the periodic table. -
Neils bohr
a model of the atom in which the electron was able to occupy only certain orbits around the nucleus. Which was the first to use quantum theory, in that the electrons were limited to specific orbits around the nucleus -
Albert Einstien
famous for devising his theory of relativity, which revolutionized our understanding of space, time, gravity, and the universe. Also invented the fridgerator. -
Schrodinger Equation
formulated a wave equation that accurately calculated the energy levels of electrons in atoms. -
Electron Cloud Model
The electron cloud model was developed by Erwin Schrödinger and Werner Heisenberg. -
Werner Heisenberg
formulated the quantum theory of ferromagnetism, the neutron-proton model of the nucleus -
James Chadwick
discovery of the neutron, a particle with no electric charge that, along with positively charged protons, makes up an atom's nucleus
