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  2. Octane rating - Wikipedia

    en.wikipedia.org/wiki/Octane_rating

    Another type of octane rating, called Motor Octane Number (MON), is determined at 900 rpm engine speed instead of the 600 rpm for RON. [2] MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, higher engine speed, and variable ignition timing to further stress the fuel's knock resistance.

  3. Octane - Wikipedia

    en.wikipedia.org/wiki/Octane

    Octane is a hydrocarbon and an alkane with the chemical formula C 8 H 18, and the condensed structural formula CH 3 (CH 2) 6 CH 3. Octane has many structural isomers that differ by the location of branching in the carbon chain. One of these isomers, 2,2,4-trimethylpentane (commonly called iso-octane), is used as one of the standard values in ...

  4. Atomicity (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Atomicity_(chemistry)

    Atomicity is the total number of atoms present in a molecule of an element. For example, each molecule of oxygen (O 2) is composed of two oxygen atoms. Therefore, the atomicity of oxygen is 2. [1] In older contexts, atomicity is sometimes equivalent to valency. Some authors also use the term to refer to the maximum number of valencies observed ...

  5. List of straight-chain alkanes - Wikipedia

    en.wikipedia.org/wiki/List_of_straight-chain_alkanes

    Number of C atoms Number of isomers [3] [4] Number of isomers including stereoisomers [3] [5] Molecular Formula Name of straight chain Synonyms 1 1 1 CH 4: methane: methyl hydride; natural gas 2 1 1 C 2 H 6: ethane: dimethyl; ethyl hydride; methyl methane 3 1 1 C 3 H 8: propane: dimethyl methane; propyl hydride 4 2 2 C 4 H 10: n-butane: butyl ...

  6. Atomic number - Wikipedia

    en.wikipedia.org/wiki/Atomic_number

    For ordinary nuclei composed of protons and neutrons, this is equal to the proton number (n p) or the number of protons found in the nucleus of every atom of that element. The atomic number can be used to uniquely identify ordinary chemical elements. In an ordinary uncharged atom, the atomic number is also equal to the number of electrons.

  7. Coordination number - Wikipedia

    en.wikipedia.org/wiki/Coordination_number

    The ion/molecule/atom surrounding the central ion/molecule/atom is called a ligand. This number is determined somewhat differently for molecules than for crystals. For molecules and polyatomic ions the coordination number of an atom is determined by simply counting the other atoms to which it is bonded (by either single or multiple bonds). [1]

  8. Octet rule - Wikipedia

    en.wikipedia.org/wiki/Octet_rule

    The bonding in carbon dioxide (CO 2): all atoms are surrounded by 8 electrons, fulfilling the octet rule.. The octet rule is a chemical rule of thumb that reflects the theory that main-group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.

  9. Electron counting - Wikipedia

    en.wikipedia.org/wiki/Electron_counting

    Ionic counting assumes unequal sharing of electrons in the bond. The more electronegative atom in the bond gains electron lost from the less electronegative atom. This method begins by calculating the number of electrons of the element, assuming an oxidation state. E.g. for a Fe 2+ has 6 electrons S 2− has 8 electrons