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  2. Crystal structure - Wikipedia

    en.wikipedia.org/wiki/Crystal_structure

    In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. [1] Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat along the principal directions of three-dimensional space in matter.

  3. Nuclear fission - Wikipedia

    en.wikipedia.org/wiki/Nuclear_fission

    A schematic nuclear fission chain reaction. 1. A uranium-235 atom absorbs a neutron and fissions into two new atoms (fission fragments), releasing three new neutrons and some binding energy. 2. One of those neutrons is absorbed by an atom of uranium-238 and does not continue the reaction. Another neutron is simply lost and does not collide with ...

  4. Atom - Wikipedia

    en.wikipedia.org/wiki/Atom

    There are two types of quarks in atoms, each having a fractional electric charge. Protons are composed of two up quarks (each with charge + ⁠ 2 / 3 ⁠) and one down quark (with a charge of − ⁠ 1 / 3 ⁠). Neutrons consist of one up quark and two down quarks. This distinction accounts for the difference in mass and charge between the two ...

  5. Nuclear transmutation - Wikipedia

    en.wikipedia.org/wiki/Nuclear_transmutation

    Illustration of a proton–proton chain, from hydrogen forming deuterium, helium-3, and regular helium-4. Nuclear transmutation is the conversion of one chemical element or an isotope into another chemical element. [1] Nuclear transmutation occurs in any process where the number of protons or neutrons in the nucleus of an atom is changed.

  6. Electron transfer - Wikipedia

    en.wikipedia.org/wiki/Electron_transfer

    Furthermore, theories have been put forward to take into account the effects of vibronic coupling on electron transfer, in particular, the PKS theory of electron transfer. [10] In proteins, ET rates are governed by the bond structures: the electrons, in effect, tunnel through the bonds comprising the chain structure of the proteins.

  7. Nuclear magnetic resonance spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Nuclear_magnetic_resonance...

    Similarly, the CH 2 is split into a quartet with an intensity ratio of 1:3:3:1 by the three neighboring CH 3 protons. In principle, the two CH 2 protons would also be split again into a doublet to form a doublet of quartets by the hydroxyl proton, but intermolecular exchange of the acidic hydroxyl proton often results in a loss of coupling ...

  8. Nuclear fission product - Wikipedia

    en.wikipedia.org/wiki/Nuclear_fission_product

    The sum of the atomic mass of the two atoms produced by the fission of one fissile atom is always less than the atomic mass of the original atom. This is because some of the mass is lost as free neutrons, and once kinetic energy of the fission products has been removed (i.e., the products have been cooled to extract the heat provided by the reaction), then the mass associated with this energy ...

  9. Water splitting - Wikipedia

    en.wikipedia.org/wiki/Water_splitting

    In thermolysis, water molecules split into hydrogen and oxygen. For example, at 2,200 °C (2,470 K; 3,990 °F) about three percent of all H 2 O are dissociated into various combinations of hydrogen and oxygen atoms, mostly H, H 2, O, O 2, and OH. Other reaction products like H 2 O 2 or HO 2 remain minor. At the very high temperature of 3,000 ...