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Discovered:that all matter is made up of small indestructible units he called Atoms
observed :that the universe is composed of two elements and contributed :help people understand the concept of an atom -
Observed: all elements consisted of atoms
Discovered: how atoms interacted and the weight contributed that each mass and size were based on on its element
Contributed: each mass and size wee different based on its element -
Discovered: canal rays
Observed: canal rays which have positive charge equal to an electron
Contributed: led to the discovery of a proton -
Discovered: Studied "canal rays" were actually electrons
Observation: He was investigating a long-standing puzzle known as "cathode rays.
Contribution : the rays were made up of electrons.mysterious rays are streams of particles much smaller than atoms, that are minuscule pieces of atoms. -
Discovered alpha beta and gamma rays in radiation.
Observations: properties of each element could be defined by this number. Each element could then be assigned and atomic number
contributed: the Rutherford model of an atom which sparked the idea of neutrons in the atom -
Discovered: identified the negatively charged electron in the cathode ray tube
Observed:the electron was a component of all matter and calculated the charge to mass ratio for the electron.
Contribution:came as a result of his oil-drop experiment, which measured an electron's charge. -
Observed:x-ray specs Chad to study atomic structure
concluded:that there were three unknown elements between aluminum and gold
Contribution:Moseley was able to determine the number of positive charges in the nucleus of an atom. The first form of atomic number -
Discovered: electrons stay in stable orbits around the atomic nucleus but can jump from one energy level to another.
Observed: observed an atomic structure theory that showed the outer orbit of an atom could hold more electrons than the inner orbit
Contributed:by the Bohr model of an atom Electrons should move around the nucleus but only in prescribed orbits. -
Discovered that electrons had a dual nature-similar to both particles and waves. Particle/wave duality.
Observations: worked on extensions of wave mechanics
Contributions that electrons could behave as waves under some conditions -
Discovered: introduced "wave mechanics" as a mathematical model of the atom.
Observations: Viewed electrons as continuous clouds and introduced
Contributions used mathematical equations to describe the likelihood of finding an electron in a certain position. -
Discoveries:Using alpha particles discovered a neutral atomic particle with a mass close to a proton
Observations:joined Rutherford in accomplishing the transmutation of other light elements by bombardment with alpha particles,
Contributed:to the discovery of the neutron -
Buescher, Lee. "Atomic Structure Timeline." Atomic Structure Timeline. N.p., n.d. Web. 02 Nov. 2016. Type, By Print. "Barcodes,Inc." A Timeline on Atomic Structure. N.p., n.d. Web. 02 Nov. 2016.
