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Democritus
Democritus was the first to suggest the idea of atoms. According to Democritus atoms were miniscule quantities of matter. Democritus hypothesized that atoms are indivisible and indestructible. He believed that there are an infinite number of atoms. (note- 465 BC) -
Robert Boyle
Robert Boyle was a born Irish man and he was a scientist who studied alchemy, biologdy and modern day chemistry and is reffered to as the father of chemistry. What he did to the atomic theory was define the difference between a compound and a solution defining how things are made up through different methods. -
Antoine Lavoisier
Antoine Lavoisier was a 18th century french chemist and was one of the first people to propose the "conservasion of mass" which states that mass through a chemical reaction stays constant. This involves atoms because it means when atoms react with other atoms no new mass is made it is only changed. He was killed by a guitine in france because he was believed to be supporting the revolution. -
John Dalton
English meteorologist and chemist John Dalton formulated the first modern description of an atom as the fundamental building blocks of stuff. He introduced a theory that said that elements differed due to the mass of their atoms. He also stated that atoms were indivisible, identical (atoms of the same element), atoms combine in whole numbers, and you cannot destroy them. -
Dmitri Mendeleev
He was a russian scientist who lived from 1834 to 1907. He organized the periodic table by atomic mass and it was named Principles of Chemistry. He was appointed professorship for this and his way of orgainizing elements is still used today. -
Eugen Goldstein
Eugen Goldstein was a german physicist who discovered atoms are mostly empty space. He found out that nuetrons and protons are in the center aka the nucleus and electrons are around it and the electrons acount for most the volume but there is a lot of space inbetween the 2. He discovered the proton. -
JJ Thomson
Thomson was a british physicist who discovered the electron in experiments that he performed in a high vacuum tube, what he found was the cathode ray and discovered the ray was magnetic. He later used this information to say that the atom was shaped like a sphere in 1904 and atoms have electrons around it. -
Max Planck
German physicist Max Planck proposed the quantum of action, now known as Planck's constant h, explaining the pattern of light intensity emitted from a black body at any given frequency. -
Rutherford
Ernest Rutherford discovederd that electrons orbit around the atom like planets to the sun and the model was called Rutherfords Atom. He did an experiment with gold foil and when he shot a lazer through it he found out most passed strait through while a select few were deflected confirming nucleus was inside. -
Henry Moseley
Henry Moseley was a english chemist and physicist who learned from Rutherford. He developed a way to use x-rays on atoms to more closely determine their their atomic structure resulting in more accurate placements of the elements on the periodic table. -
Robert Millikan
Robert Millikan was an American born and studied at various univiersites throughout the world. He discovered a way to accuratly determine the mass and charge of an electron. He did this using the "falling drop method". He also said that is quanity is same for all electrons on any atom. -
NIels Bohr
Niels Bohr earned a nobel prize for explaining what happens inside an atom and developed a picture of atomic structure. Bohr's greatest contribution to modern physics was the atomic model. The Bohr model shows the atom with a small, positively charged nucleus surrounded by orbiting electrons. Bohr was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element. -
Erwin Schrodinger
Erwin Schrödinger, an Austrian physicist, developed the Bohr atom model further. He used mathematical equations to describe the likelihood of finding an electron in a certain position. This atomic model is known as the quantum mechanical model of the atom and includes the idea of the electron cloud. Where the cloud is densest, the probability is highest. -
James Chadwick
James Chadwick focused on radioactivity, Following the work of Ernest Rutherford, he focused on the nucleus of the atom and after doing tests on atomic weight he discovered the neutron. Chadwick discovered that the neutron had zero charge, were located in the nucleus, and had the same mass as protons. -
Joe and Casey's and Timeline Project
Joe Foye and Casey Wisniewski do a timeline project for Mrs. Hujer's 5th hour chemistry class. Their revolutionary delving into the history of atomic structure is earth shattering and will live on for centuries to come.
