-
440
Democritus discovers that atom.
The greek philosopher Democritus discoverd the atom and claimed that atoms were small, hard particles that couldn't be divided and made up all matter. 440 BCE -
Dalton's Atom
Dalton, a british scientist and teacher, reintroduced the concept of the atom as small particles that make up matter and can not be created, divided or destroyed. also that atoms of the same element are exactly alike and atoms of different elements are completely different. 1803 -
Periodic Table Invented
A Rusain chemist named Demetri Mendeleev created the periodic table with the elements known at the time. -
Electrons Discovered in " Plum and Pudding" Atom
British scientist J.J. Thompson discovers a flaw in Daltons atom. He discovered small particles inside the atom. He experimented with a cathode-ray tube. He found that a positively charged plate attracted the beam. Thomson concluded that the beam was made of particles that have negative electric charges. He then concluded that these negatively charged particles are in every kind of atom. These negatively charged particles are now called electrons. -
Ruthford's experiment
Ernest Rithford, a former student of Thompson's, started with Thompson's theory on Atoms being soft "blobs' and then advanced into his own idead after onducting an experiment in which he aimed a beam of small, positively charged particles at a thin sheet of gold foil.The coating glowed when hit by the positively charged particles. Rutherford could then see where the particles went after hitting the gold. -
Ruthford's Atom
In 1911, Rutherford revised the atomic theory. He made a new model of the atom. He proposed that in the center of the atom is a tiny, extremely dense, positively charged part called the nucleus. Because like charges repel, Rutherford reasoned that positively charged particles that passed close by the nucleus were pushed away by the positive charges in the nucleus. -
Bohr's Atom
Bohr's atom was the named galaxy model lso known as the planetary model) due to its Galaxy like shape. his research and model wh=ere based of off the movements of the electron. -
Chadwick's Atom
James chadwick discovered Neutrons in the atom's nucleaus, whick play a key part in splitting an atom and in the atoms physical make-up. -
First atom seen
Scientist in Switzerland invent a microscope in which an atom can be seen.
