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This is a timeline of subatomic particle discoveries, including all particles thus far discovered which appear to be elementary (that is, indivisible) given the best available evidence. It also includes the discovery of composite particles and antiparticles that were of particular historical importance.
Scientists eventually discovered that atoms have a positively charged nucleus (with an atomic number of charges) in the center, with a radius of about 1.2 × 10 −15 meters × [atomic mass number] 1 ⁄ 3. Electrons were found to be even smaller.
1918 Ernest Rutherford notices that, when alpha particles were shot into nitrogen gas, his scintillation detectors showed the signatures of hydrogen nuclei. 1921 Alfred Landé introduces the Landé g-factor; 1922 Arthur Compton studies X-ray photon scattering by electrons demonstrating the 'particle' aspect of electromagnetic radiation.
1902 – To explain the octet rule (1893), Gilbert N. Lewis develops the "cubical atom" theory in which electrons in the form of dots are positioned at the corner of a cube. Predicts that single, double, or triple "bonds" result when two atoms are held together by multiple pairs of electrons (one pair for each bond) located between the two atoms.
Nor was he aware of valencies. These properties of atoms were discovered later in the 19th century. [citation needed] Because atoms were too small to be directly weighed using the methods of the 19th century, Dalton instead expressed the weights of the myriad atoms as multiples of the hydrogen atom's weight, which Dalton knew was the lightest ...
Even elementary particles can decay or collide destructively; they can cease to exist and create (other) particles in result. Increasingly small particles have been discovered and researched: they include molecules, which are constructed of atoms, that in turn consist of subatomic particles, namely atomic nuclei and electrons. Many more types ...
This timeline lists significant discoveries in physics and the laws of nature, including experimental discoveries, theoretical proposals that were confirmed experimentally, and theories that have significantly influenced current thinking in modern physics. Such discoveries are often a multi-step, multi-person process.
1928 – Felix Bloch applies quantum mechanics to electrons in crystal lattices, establishing the quantum theory of solids [7] 1929 – Paul Adrien Maurice Dirac [citation needed] and Werner Karl Heisenberg develop the quantum theory of ferromagnetism [8] 1932 – Louis Eugène Félix Néel discovers antiferromagnetism [9]