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  2. Glossary of chemistry terms - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_chemistry_terms

    [4] amphoteric. Also amphiprotic. (of a chemical species) Tending to behave both as an acid and as a base, depending upon the medium in which the species is situated; e.g. sulfuric acid (H 2 SO 4) is a strong acid in water but behaves more like a base in superacids. amyl A common non-systematic name for a pentyl group. analyte

  3. Molecule - Wikipedia

    en.wikipedia.org/wiki/Molecule

    In the simplest case, the cation is a metal atom and the anion is a nonmetal atom, but these ions can be of a more complicated nature, e.g. molecular ions like NH 4 + or SO 4 2−. At normal temperatures and pressures, ionic bonding mostly creates solids (or occasionally liquids) without separate identifiable molecules, but the vaporization ...

  4. CHNOPS - Wikipedia

    en.wikipedia.org/wiki/CHNOPS

    Graphic representation of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. CHNOPS and CHON are mnemonic acronyms for the most common elements in living organisms. . "CHON" stands for carbon, hydrogen, oxygen, and nitrogen, which together make up more than 95 percent of the mass of biological system

  5. Biological roles of the elements - Wikipedia

    en.wikipedia.org/wiki/Biological_roles_of_the...

    A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]

  6. Glossary of biology - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_biology

    This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms.It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology ...

  7. Valence electron - Wikipedia

    en.wikipedia.org/wiki/Valence_electron

    Four covalent bonds.Carbon has four valence electrons and here a valence of four. Each hydrogen atom has one valence electron and is univalent. In chemistry and physics, valence electrons are electrons in the outermost shell of an atom, and that can participate in the formation of a chemical bond if the outermost shell is not closed.

  8. Chemical formula - Wikipedia

    en.wikipedia.org/wiki/Chemical_formula

    A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus (+) and minus (−) signs.

  9. Chemical composition - Wikipedia

    en.wikipedia.org/wiki/Chemical_composition

    A chemical composition specifies the identity, arrangement, and ratio of the chemical elements making up a compound by way of chemical and atomic bonds.. Chemical formulas can be used to describe the relative amounts of elements present in a compound.