-
300
Democritus
first to sugest the idea of the atom. he thought that it was indivisable and indestructable. -
Period: 300 to
timespan
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Robert Boyle
Boyle carried out various experiments which helped him in the discovery of the relationship between pressure and volume of gases. This resulted in the “Boyle-Mariotte Law”. also which implies that if the temperature is constant, the volume of gas is inversely proportional to the pressure. -
Antoine Lavoiser
Lavoisier found that mass is conserved in a chemical reaction.The total mass of the products of a chemical reaction is always the same as the total mass of the starting materials consumed in the reaction. His results led to one of the fundamental laws of chemical behavior: the law of conservation of matter, which states that matter is conserved in a chemical reaction. -
John Dalton
discovered that the atom is indivisable, atoms are identicle that are the same element. he put Democratus's idea of the atom into a theory. he studied the status in which elements combine in chemical reactions. -
Dmitri mendeleev
Mendeleev listed the elements in columns in order of increasing atomic mass. He then rearranged the columns so that the elements with the most similar chemical properties were side by side. This correctly arranged the elements, with many blank spaces remaining in between. -
Eugen Goldstein
he figured out
electron(e-) -1
Proton(P+) +1
Nuetron(n) 0 -
Max Plank
Planck's discovery was that energy, which appears to be emitted in wavelengths, is actually discharged in small packets. This new theory of energy revolutionized physics and opened the way for Albert Einstein's theory of relativity. -
JJ Tomson
he discovered the electron and that it had a negative charge. his model is known as the plum pudding model because of the good pudding and the plums spread out throughout it just like the electrons in the atom. -
Robert Millikan
Robert Millikan discovered the mass and the charge of an electron. he made an expierement to test his hypothesies and he called it the oil drop expierement. he discovered that the electron is 1/1800th. of the mass of a proton. -
Niels Bohr
he proposed a theory the hydrogen atom based on
quantum physics that energy is transferred only in
certain well defined quantities. electrons should
move around the nucleus but only in prescribed
orbits. when jumping from one orbit to another with
low energy, a light quantum is emitted. Bohr’s
theory could explain why atoms emitted light in fixed
lengths. -
Henry Moseley
Henry Moseley is known for his establishment of truly scientific basis of the Periodic Table of the Elements by sorting chemical elements in the order of their atomic numbers. -
James Chadwick
he discovered the nuetron. he discovered that the nuetron has no charge, it is located in the nucleous and that it is the same mass of a proton -
Ernest Rutherford
He discovered alpha and beta rays, set by the laws of radioactive decay, and identified alpha particles as helium nuclei. he showed that when alpha particles are fired into gas atoms, a few are violently deflected, which implies a dense, positively charged central region containing most of the atomic mass. -
Erwin Schrodinger
