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Democritus
Democritus was a Greek who theorized that matter was made up of small particles that had empty space around them. He deemed them "atomos", the Greek word for indivisible. He also thought that they could potentially be differently shaped depending on what material they made up. Although a precursor to the truths of atoms, his ideas were declared wrong and it wasn't until many years later that this ideas were touched up again. -
John Dalton
John Dalton was a Quaker teacher who wanted to challenge the current belief of elements and how they stood in science. To prove his ideas, he ran tests that showed that certain substances always broke down into the same amounts of the elements they were comprised of. This helped him solidify Atomic Theory, and have it be accepted by the general science world. -
Joeseph Thompson
Joespeh Thompson is a scientist who discovered the existence of the electron. He did this through testing the nature of electronic disagree with cathode-ray tubes in a vaccum. This lead him to believe that atoms were made up of a large central mass, with electrons embedded in the surface. He won't a Nobel Prize for his discovery of the electron, but was to be disproven in the future of his model of the atom. -
Ernest Rutherford
Known as "Father of the Nuclear Age", Rutherford is responsible for the discovery of the nucleus and that electrons are spaced around the nucleus. He found this out by shooting alpha particles at a piece of gold foil. He theorized that all the particles like would punch through, as the atom wouldn't be able to stop them. Yet some particles bounced back, suggesting a different structure of atoms. -
Niels Bohr
Niels Bohr expanded on the discoveries of Rutherford, and through tests , suggested that electrons orbited the atom at fixed energy levels away from it. While wrong, this lead to the eventual discovery that electrons act like waves, and travel erratically around the nucleus.