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John Dalton
-Matter made of small indivisible atoms
-Atoms can’t be subdivided, created, destroyed
-Atoms of different elements can form compounds -
Marie Curie
-Discovered radioactivity, and resulted in dying to it.
-Received 2 nobel prizes, one for physics and one for chemistry -
JJ Thomson
-An atom is electrically neutral, no charge.
-Both positive and negative charges are equal in the atom
-An atom is made out of a sphere of positive charges with negatively charged electron embedded in it -
Robert Milikan
-Precisely determined the magnitude of the electron charge
-Received Nobel Prize for “his work on the elementary charge of electricity and on the photoletric effect -
Ernest Rutherford
-Atoms are mostly empty space
-Most of the mass is concentrated in the center of the atom, which is called the nucleus
-Electrons are located outside the nucleus. -
Neils Bohr
-Electrons orbit the nucleus in orbits that have specific shape and size
-The energy of the orbit is related to its size. The lowest energy is found in the smallest orbit.
-Electrons move in orbits, they move between shells when gaining or losing energy -
Erwin Schrodinger
-Electrons don’t move around the nucleus in orbits
-Electrons exist in a cloud with specific energy levels
-The electron cloud exists in a region with negative charges only, surrounding the nucleus. -
James Chadwick
-Discovered the neutron and its mass
-Worked with Ernest Rutherford -
Werner Heisenburg
-Awarded Nobel prize in 1932
-Involved with the theory of quantum mechanics