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  2. Outline of chemistry - Wikipedia

    en.wikipedia.org/wiki/Outline_of_chemistry

    Organic chemistry (outline) – study of the structure, properties, composition, mechanisms, and reactions of organic compounds. An organic compound is defined as any compound based on a carbon skeleton. Biochemistry – study of the chemicals, chemical reactions and chemical interactions that take place in living organisms.

  3. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    Elements. The main elements that comprise the human body (including water) can be summarized as CHNOPS. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium.

  4. Quantum number - Wikipedia

    en.wikipedia.org/wiki/Quantum_number

    An electron state has spin number s = ⁠ 1 / 2 ⁠, consequently m s will be + ⁠ 1 / 2 ⁠ ("spin up") or - ⁠ 1 / 2 ⁠ "spin down" states. Since electron are fermions they obey the Pauli exclusion principle: each electron state must have different quantum numbers. Therefore every orbital will be occupied with at most two electrons, one ...

  5. State of matter - Wikipedia

    en.wikipedia.org/wiki/State_of_matter

    In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma. Many intermediate states are known to exist, such as liquid crystal, and some states only exist under extreme conditions, such as Bose–Einstein condensates and Fermionic ...

  6. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    t. e. The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows ("periods") and columns ("groups"). It is an icon of chemistry and is widely used in physics and other sciences. It is a depiction of the periodic law, which states that when the elements are arranged in order ...

  7. Isotopes of nitrogen - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_nitrogen

    Natural nitrogen (7 N) consists of two stable isotopes: the vast majority (99.6%) of naturally occurring nitrogen is nitrogen-14, with the remainder being nitrogen-15. Thirteen radioisotopes are also known, with atomic masses ranging from 9 to 23, along with three nuclear isomers. All of these radioisotopes are short-lived, the longest-lived ...

  8. Chemical element - Wikipedia

    en.wikipedia.org/wiki/Chemical_element

    A chemical element is a chemical substance that cannot be broken down into other substances by chemical reactions. The basic particle that constitutes a chemical element is the atom. Elements are identified by the number of protons in their nucleus, [1] known as the element's atomic number. [2] For example, oxygen has an atomic number of 8 ...

  9. CHNOPS - Wikipedia

    en.wikipedia.org/wiki/CHNOPS

    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 c arbon, h ydrogen, o xygen, and n itrogen, which together make up more than 95 percent of the mass of biological systems. [1] ".