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• Democritus proposes the concept of atoms as indivisible particles that make up all matter.
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• Alchemists explore the transmutation of metals in search of the philosopher's stone, a legendary substance believed to possess transformative powers.
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• J.J. Thomson conducts experiments with cathode rays and discovers the existence of negatively charged particles called electrons.
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• Ernest Rutherford and his team conduct an experiment in which they shoot alpha particles at a thin gold foil, leading to the discovery that most of the atom's mass and positive charge are concentrated in its nucleus.
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• Niels Bohr proposes a model of the atom where electrons orbit the nucleus in discrete energy levels, and the emission or absorption of energy occurs when electrons transition between these levels.
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• Scientists, including Max Planck, Albert Einstein, and Erwin Schrödinger, develop the principles of quantum mechanics, which describe the wave-particle duality of matter and energy.
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• James Chadwick discovers the neutral particle called the neutron, which contributes to the mass of the atomic nucleus.
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• Particle accelerators and detectors lead to the discovery of various subatomic particles, including protons, neutrons, mesons, and baryons.
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• Scientists formulate the Standard Model of particle physics, which describes the fundamental particles of matter (quarks, leptons) and their interactions through electromagnetic, weak, and strong forces.
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• Ongoing research at particle accelerators, such as the Large Hadron Collider (LHC), continues to explore the properties of subatomic particles and search for new particles or phenomena beyond the Standard Model.
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• The quest to understand the atom and its fundamental constituents is an ongoing endeavor, with future breakthroughs likely to expand our knowledge and deepen our understanding of the universe.