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  2. Hückel method - Wikipedia

    en.wikipedia.org/wiki/Hückel_method

    To summarize, we are assuming that: (1) the energy of an electron in an isolated C(2p z) orbital is =; (2) the energy of interaction between C(2p z) orbitals on adjacent carbons i and j (i.e., i and j are connected by a σ-bond) is =; (3) orbitals on carbons not joined in this way are assumed not to interact, so = for nonadjacent i and j; and ...

  3. Elemental analysis - Wikipedia

    en.wikipedia.org/wiki/Elemental_analysis

    [citation needed] Elemental analysis can be qualitative (determining what elements are present), and it can be quantitative (determining how much of each is present). Elemental analysis falls within the ambit of analytical chemistry, the instruments involved in deciphering the chemical nature of our world.

  4. Charge number - Wikipedia

    en.wikipedia.org/wiki/Charge_number

    is used as the symbol for the charge number. In that case, the charge of an ion could be written as =. The charge number in chemistry normally relates to an electric charge. This is a property of specific subatomic atoms. These elements define the electromagnetic contact between the two elements.

  5. Ion transport number - Wikipedia

    en.wikipedia.org/wiki/Ion_transport_number

    The anode reaction is Cd → Cd 2+ + 2 e − so that a cadmium chloride (CdCl 2) solution is formed near the anode and moves toward the cathode during the experiment. An acid-base indicator such as bromophenol blue is added to make visible the boundary between the acidic HCl solution and the near-neutral CdCl 2 solution. [8]

  6. Mass-to-charge ratio - Wikipedia

    en.wikipedia.org/wiki/Mass-to-charge_ratio

    When charged particles move in electric and magnetic fields the following two laws apply: Lorentz force law: = (+),; Newton's second law of motion: = =; where F is the force applied to the ion, m is the mass of the particle, a is the acceleration, Q is the electric charge, E is the electric field, and v × B is the cross product of the ion's velocity and the magnetic flux density.

  7. d electron count - Wikipedia

    en.wikipedia.org/wiki/D_electron_count

    The d electron count or number of d electrons is a chemistry formalism used to describe the electron configuration of the valence electrons of a transition metal center in a coordination complex. [ 1 ] [ 2 ] The d electron count is an effective way to understand the geometry and reactivity of transition metal complexes.

  8. Degree of unsaturation - Wikipedia

    en.wikipedia.org/wiki/Degree_of_unsaturation

    For hydrocarbons, the DBE (or IHD) tells us the number of rings and/or extra bonds in a non-saturated structure, which equals the number of hydrogen pairs that are required to make the structure saturated, simply because joining two elements to form a ring or adding one extra bond (e.g., a single bond changed to a double bond) in a structure reduces the need for two H's.

  9. Electron transfer - Wikipedia

    en.wikipedia.org/wiki/Electron_transfer

    The first generally accepted theory of ET was developed by Rudolph A. Marcus (Nobel Prize in Chemistry in 1992) [8] to address outer-sphere electron transfer and was based on a transition-state theory approach. The Marcus theory of electron transfer was then extended to include inner-sphere electron transfer by Noel Hush and Marcus.