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  2. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    The main elements that comprise the human body (including water) can be summarized as CHNOPS. Element Symbol percent mass percent atoms Oxygen O 65.0 24.0 Carbon C 18.5 12.0 Hydrogen H 9.5 62.0 Nitrogen N 2.6 1.1 Calcium Ca 1.3 0.22 Phosphorus P 0.6 0.22 Sulfur S 0.3 0.038 Potassium K 0.2 0.03 Sodium Na 0.2 0.037 Chlorine Cl 0.2 0.024 Magnesium Mg

  3. Atom - Wikipedia

    en.wikipedia.org/wiki/Atom

    This is a form of nuclear decay. Atoms can attach to one or more other atoms by chemical bonds to form chemical compounds such as molecules or crystals. The ability of atoms to attach and detach from each other is responsible for most of the physical changes observed in nature. Chemistry is the science that studies these changes.

  4. Human body - Wikipedia

    en.wikipedia.org/wiki/Human_body

    Human anatomy is the study of the shape and form of the human body. The human body has four limbs (two arms and two legs), a head and a neck, which connect to the torso. The body's shape is determined by a strong skeleton made of bone and cartilage, surrounded by fat (adipose tissue), muscle, connective tissue, organs, and

  5. Chemical bond - Wikipedia

    en.wikipedia.org/wiki/Chemical_bond

    Examples of Lewis dot diagrams used to represent electrons in the chemical bonds between atoms, here showing carbon (C), hydrogen (H), and oxygen (O). Lewis diagrams were developed in 1916 by Gilbert N. Lewis to describe chemical bonding and are still widely used today. Each line segment or pair of dots represents a pair of electrons.

  6. Chemical structure - Wikipedia

    en.wikipedia.org/wiki/Chemical_structure

    The methods by which one can determine the structure of a molecule is called structural elucidation.These methods include: concerning only connectivity of the atoms: spectroscopies such as nuclear magnetic resonance (proton and carbon-13 NMR), various methods of mass spectrometry (to give overall molecular mass, as well as fragment masses).Techniques such as absorption spectroscopy and the ...

  7. Structural formula - Wikipedia

    en.wikipedia.org/wiki/Structural_formula

    Skeletal structural formula of Vitamin B 12.Many organic molecules are too complicated to be specified by a molecular formula.. The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are possibly arranged in the real three-dimensional space.

  8. Lewis structure - Wikipedia

    en.wikipedia.org/wiki/Lewis_structure

    Another shorthand structural diagram is the skeletal formula (also known as a bond-line formula or carbon skeleton diagram). In a skeletal formula, carbon atoms are not signified by the symbol C but by the vertices of the lines. Hydrogen atoms bonded to carbon are not shown—they can be inferred by counting the number of bonds to a particular ...

  9. Nuclear structure - Wikipedia

    en.wikipedia.org/wiki/Nuclear_structure

    The main idea of the Independent Particle approach is that a nucleon moves inside a certain potential well (which keeps it bound to the nucleus) independently from the other nucleons. This amounts to replacing an N-body problem (N particles interacting) by N single-body problems. This essential simplification of the problem is the cornerstone ...