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  2. Valence electron - Wikipedia

    en.wikipedia.org/wiki/Valence_electron

    An atom with one or two electrons fewer than a closed shell is reactive due to its tendency either to gain the missing valence electrons and form a negative ion, or else to share valence electrons and form a covalent bond. Similar to a core electron, a valence electron has the ability to absorb or release energy in the form of a photon.

  3. Valence (chemistry) - Wikipedia

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

    The valence is the combining capacity of an atom of a given element, determined by the number of hydrogen atoms that it combines with. In methane, carbon has a valence of 4; in ammonia, nitrogen has a valence of 3; in water, oxygen has a valence of 2; and in hydrogen chloride, chlorine has a valence of 1.

  4. Electron counting - Wikipedia

    en.wikipedia.org/wiki/Electron_counting

    conclusion: Methane follows the octet-rule for carbon, and the duet rule for hydrogen, and hence is expected to be a stable molecule (as we see from daily life) H 2 S, for the central S; neutral counting: S contributes 6 electrons, each hydrogen radical contributes one each: 6 + 2 × 1 = 8 valence electrons

  5. 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.

  6. Hydrogen - Wikipedia

    en.wikipedia.org/wiki/Hydrogen

    Although exotic on Earth, the H + 3 ion is common in the universe. It is a triangular species, like the aforementioned dihydrogen complexes. It is known as protonated molecular hydrogen or the trihydrogen cation. [90] Hydrogen directly reacts with chlorine, fluorine and bromine to give HF, HCl, and HBr, respectively.

  7. Hydrogen compounds - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_compounds

    Hydrogen compounds are compounds containing the element hydrogen. In these compounds, hydrogen can form in the +1 and -1 oxidation states. Hydrogen can form compounds both ionically and in covalent substances. It is a part of many organic compounds such as hydrocarbons as well as water and other organic substances.

  8. Carbon–hydrogen bond - Wikipedia

    en.wikipedia.org/wiki/Carbon–hydrogen_bond

    A bond between a hydrogen atom and an sp 2 hybridised carbon atom is about 0.6% shorter than between hydrogen and sp 3 hybridised carbon. A bond between hydrogen and sp hybridised carbon is shorter still, about 3% shorter than sp 3 C-H. This trend is illustrated by the molecular geometry of ethane, ethylene and acetylene. [citation needed]

  9. 18-electron rule - Wikipedia

    en.wikipedia.org/wiki/18-electron_rule

    Compounds that obey the 18-electron rule are typically "exchange inert". Examples include [Co(NH 3) 6]Cl 3, Mo(CO) 6, and [Fe(CN) 6] 4−. In such cases, in general ligand exchange occurs via dissociative substitution mechanisms, wherein the rate of reaction is determined by the rate of dissociation of a ligand. On the other hand, 18-electron ...