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  2. Allotropes of carbon - Wikipedia

    en.wikipedia.org/wiki/Allotropes_of_carbon

    Prismane C 8 is a theoretically predicted metastable carbon allotrope comprising an atomic cluster of eight carbon atoms, with the shape of an elongated triangular bipyramid—a six-atom triangular prism with two more atoms above and below its bases. [45] Protomene: A

  3. Isotopes of carbon - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_carbon

    Carbon (6 C) has 14 known isotopes, from 8 C to 20 C as well as 22 C, of which 12 C and 13 C are stable.The longest-lived radioisotope is 14 C, with a half-life of 5.70(3) × 10 3 years. . This is also the only carbon radioisotope found in nature, as trace quantities are formed cosmogenically by the reactio

  4. AP Chemistry - Wikipedia

    en.wikipedia.org/wiki/AP_Chemistry

    The 2014 AP Chemistry exam was the first administration of a redesigned test as a result of a redesigning of the AP Chemistry course. The exam format is now different from the previous years, with 60 multiple choice questions (now with only four answer choices per question), 3 long free response questions, and 4 short free response questions.

  5. Crystal structure - Wikipedia

    en.wikipedia.org/wiki/Crystal_structure

    The crystallographic point group or crystal class is the mathematical group comprising the symmetry operations that leave at least one point unmoved and that leave the appearance of the crystal structure unchanged. These symmetry operations include Reflection, which reflects the structure across a reflection plane

  6. Physical chemistry - Wikipedia

    en.wikipedia.org/wiki/Physical_chemistry

    Physical chemistry, in contrast to chemical physics, is predominantly (but not always) a supra-molecular science, as the majority of the principles on which it was founded relate to the bulk rather than the molecular or atomic structure alone (for example, chemical equilibrium and colloids).

  7. Molecular orbital theory - Wikipedia

    en.wikipedia.org/wiki/Molecular_orbital_theory

    The atomic orbital combination must have the correct symmetry, which means that it must belong to the correct irreducible representation of the molecular symmetry group. Using symmetry adapted linear combinations, or SALCs, molecular orbitals of the correct symmetry can be formed. Atomic orbitals must also overlap within space.

  8. Electron configuration - Wikipedia

    en.wikipedia.org/wiki/Electron_configuration

    In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. [1] For example, the electron configuration of the neon atom is 1s 2 2s 2 2p 6 , meaning that the 1s, 2s, and 2p subshells are occupied by two, two, and six ...

  9. Rutherford model - Wikipedia

    en.wikipedia.org/wiki/Rutherford_model

    In a May 1911 paper, [8] Rutherford presented his own physical model for subatomic structure, as an interpretation for the unexpected experimental results. [3] In it, the atom is made up of a central charge (this is the modern atomic nucleus, though Rutherford did not use the term "nucleus" in his paper). Rutherford only committed himself to a ...