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  2. Chemical bond - Wikipedia

    en.wikipedia.org/wiki/Chemical_bond

    A coordinate covalent bond is a covalent bond in which the two shared bonding electrons are from the same one of the atoms involved in the bond. For example, boron trifluoride (BF 3) and ammonia (NH 3) form an adduct or coordination complex F 3 B←NH 3 with a B–N bond in which a lone pair of electrons on N is shared with an empty atomic ...

  3. List of chemical elements - Wikipedia

    en.wikipedia.org/wiki/List_of_chemical_elements

    A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...

  4. Molecule - Wikipedia

    en.wikipedia.org/wiki/Molecule

    The simplest of molecules is the hydrogen molecule-ion, H 2 +, and the simplest of all the chemical bonds is the one-electron bond. H 2 + is composed of two positively charged protons and one negatively charged electron , which means that the Schrödinger equation for the system can be solved more easily due to the lack of electron–electron ...

  5. Hydrogen bond - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_bond

    The hydrogen bond is an attractive interaction between a hydrogen atom from a molecule or a molecular fragment X−H in which X is more electronegative than H, and an atom or a group of atoms in the same or another molecule, in which there is evidence of bond formation.

  6. Ammonium - Wikipedia

    en.wikipedia.org/wiki/Ammonium

    The lone electron pair on the nitrogen atom (N) in ammonia, represented as a line above the N, forms a coordinate bond with a proton (H +). After that, all four NH bonds are equivalent, being polar covalent bonds. The ion has a tetrahedral structure and is isoelectronic with methane and the borohydride anion.

  7. Chemistry - Wikipedia

    en.wikipedia.org/wiki/Chemistry

    Chemistry is the scientific study of the properties and behavior of matter. [1] It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances.

  8. Chemical compound - Wikipedia

    en.wikipedia.org/wiki/Chemical_compound

    [16] [17] [18] A molecule may be homonuclear, that is, it consists of atoms of one chemical element, as with two atoms in the oxygen molecule (O 2); or it may be heteronuclear, a chemical compound composed of more than one element, as with water (two hydrogen atoms and one oxygen atom; H 2 O). A molecule is the smallest unit of a substance that ...

  9. Chemical element - Wikipedia

    en.wikipedia.org/wiki/Chemical_element

    The term "(chemical) element" is used in two different but closely related meanings: [2] it can mean a chemical substance consisting of a single kind of atoms (a free element), or it can mean that kind of atoms as a component of various chemical substances. For example, molecules of water (H 2 O) contain atoms of hydrogen (H) and oxygen (O), so ...