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  2. Hydrogen bond - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_bond

    This can repeat such that every water molecule is H-bonded with up to four other molecules, as shown in the figure (two through its two lone pairs, and two through its two hydrogen atoms). Hydrogen bonding strongly affects the crystal structure of ice, helping to create an open hexagonal lattice. The density of ice is less than the density of ...

  3. Arrow pushing - Wikipedia

    en.wikipedia.org/wiki/Arrow_pushing

    Arrow pushing or electron pushing is a technique used to describe the progression of organic chemistry reaction mechanisms. [1] It was first developed by Sir Robert Robinson.In using arrow pushing, "curved arrows" or "curly arrows" are drawn on the structural formulae of reactants in a chemical equation to show the reaction mechanism.

  4. Skeletal formula - Wikipedia

    en.wikipedia.org/wiki/Skeletal_formula

    A skeletal formula shows the skeletal structure or skeleton of a molecule, which is composed of the skeletal atoms that make up the molecule. [1] It is represented in two dimensions, as on a piece of paper. It employs certain conventions to represent carbon and hydrogen atoms, which are the most common in organic chemistry.

  5. Lewis structure - Wikipedia

    en.wikipedia.org/wiki/Lewis_structure

    A trick is to count up valence electrons, then count up the number of electrons needed to complete the octet rule (or with hydrogen just 2 electrons), then take the difference of these two numbers. The answer is the number of electrons that make up the bonds. The rest of the electrons just go to fill all the other atoms' octets.

  6. 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.

  7. Wikipedia:Reference desk/Archives/Science/2011 February 24 ...

    en.wikipedia.org/wiki/Wikipedia:Reference_desk/...

    The fact is, it is possible for H 2 to form in a collision of two hydrogen atoms, with the excess energy being shed somehow (probably as photons, but there are other ways). I guess it's unlikely, but it doesn't violate any conservation laws. Many physicists would describe this as "a collision that involves only two hydrogen atoms".

  8. Hydrogen compounds - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_compounds

    Water molecules have two hydrogen atoms and one oxygen atom. While H 2 is not very reactive under standard conditions, it does form compounds with most elements. Hydrogen can form compounds with elements that are more electronegative, such as halogens (F, Cl, Br, I), or oxygen; in these compounds hydrogen takes on a partial positive charge. [1]

  9. Chemical bonding of water - Wikipedia

    en.wikipedia.org/wiki/Chemical_bonding_of_water

    In the simple MO diagram of H 2 O, the 2s orbital of oxygen is mixed with the premixed hydrogen orbitals, forming a new bonding (2a 1) and antibonding orbital (4a 1). Similarly, the 2p orbital (b 1) and the other premixed hydrogen 1s orbitals (b 1) are mixed to make bonding orbital 1b 1 and antibonding orbital 2b 1. The two remaining 2p ...