ilovepdf_merged NEEDYUMPU

Research the Scientist and summarize their contributions to the Atomic Theory
Antoine Henri Becquerel He was the first one to be able to discover radioactivity. He discovered by accident that
uranium salts are affected by light emiting a penetrating raditation that can be registered on a
photographic plate.
Niels Bohr
Louis de Barogilie
Glenn Seaborg
Hantaro Nagaoka He came up with an alternative planetary model of the atom where the positively charged center is
surrounded by a number of revolving electrons. His model showed that an atom had a very massive
atomic center.
Democritus
Marie and Pierre Curie they started the study of radioactivity, which led to discovery of some elements on the periodic
table of elements like radium and polonium. They thought radioactivity does not depend on how
atoms are arranged into molecules, but in the atom itself.
Eugene Goldstein
Dmitri Mendeleev
J.J. Thomson
James Chadwick
Erwin Shrodinger
John Dalton
Lothar Meyer
proposed a theory that the hydrogen atom based on quantum theory. He proclaimed electrons should move
around the nucleus but only in a directed orbit.
known for research on the quantum theory and predicting the wave nature of electrons. His ideas
were the basis for develpoing the wave mechanics theory. Improved the knowledge of the physcial
nature on the atomic scale.
discovered elements such as plutonium and went on to identify several other and more of the
radioactive "transuranium" elements. discovered over 100 isotopes of elements throughout the
periodic table.
First came up with the idea that matter conisisted of tiny invisible particles called "atomos" He also created
the first atom model but it did not have the essential components of the electrons, protons, and neutrons.
Helped further the topic of atoms.
He is credited with the discovery of the proton aswell. He was a early investiigator of discharge
tubes. Discovered the anode rays.
He arranged 63 elements into the periodic table based on the atomic mass of course. Used it to put
the atomic weight and put them into columns based on physical and chemicl properties. Helps
understand the periodic table of elements more due to his contribution.
discovered electrons and noticed atoms could be divided. He made the plum pudding model These
discoveries helped forward the understanding of the atom and it's generic make up.
James attacked the berryllium atoms with alpha particles. discovered the neutron. Interpreted the
radiation as being composed of particles with neutral electrical charge and the apporximate mass
of a proton.
furthered the research on the Bohr atom model. Used mathematical equations to describe the
chances of finding an electron in a specified position. His model was called the quantum mechanical
model of the atom.
proposed the atomic theory using measurable properties of mass. remains valid in todays modern chemical
thought. the rules are 1) all matter is made of atoms. 2) indivisible and indestructable. 3) compoundsare
formed by combination of two or more different kinds of atoms.
He was one of the pioneers in developing the first periodic table of elements. Took ideas from Mendeleyev
table and formed his own table that showed the atomic weight and the properties of the element.
Robert Millikan
J.W. Dobereiner
Ernest Rutherford
as a result of his oil-drop expiriment he was able to measure the electron's charge. His contribution is
he advanced J.J Thompsons hypothesis. Also specified the size of the electrons charges.
He developed the laws of triad in 1817, he had 3 groups to find out the ralative atomic masses of the
elements.The relative mass of the middle elemen was close to the average of the other two elements
and led to important realization that atomic masses help allign the elemetns when arranging them.
discovered alpha and beta rays, also made the laws of radioactive decay. Identified that alpha
particles were also helium nuclei.
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