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  2. Acetal - Wikipedia

    en.wikipedia.org/wiki/Acetal

    In contrast to variations of R, both R' groups are organic fragments. If one R' is a hydrogen, the functional group is instead a hemiacetal, while if both are H, the functional group is a ketone hydrate or aldehyde hydrate. Formation of an acetal occurs when the hydroxyl group of a hemiacetal becomes protonated and is lost as water.

  3. Acetyl group - Wikipedia

    en.wikipedia.org/wiki/Acetyl_group

    In IUPAC nomenclature, an acetyl group is called an ethanoyl group. An acetyl group contains a methyl group ( −CH 3 ) that is single-bonded to a carbonyl ( C=O ), making it an acyl group . The carbonyl center of an acyl radical has one non-bonded electron with which it forms a chemical bond to the remainder (denoted with the letter R ) of the ...

  4. Group (periodic table) - Wikipedia

    en.wikipedia.org/wiki/Group_(periodic_table)

    a Group 1 is composed of hydrogen (H) and the alkali metals. Elements of the group have one s-electron in the outer electron shell. Hydrogen is not considered to be an alkali metal as it is not a metal, though it is more analogous to them than any other group. This makes the group somewhat exceptional.

  5. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    a Group 1 is composed of hydrogen (H) and the alkali metals. Elements of the group have one s-electron in the outer electron shell. Hydrogen is not considered to be an alkali metal as it is not a metal, though it is more analogous to them than any other group. This makes the group somewhat exceptional.

  6. Functional group - Wikipedia

    en.wikipedia.org/wiki/Functional_group

    The reactivity of a functional group can be modified by other functional groups nearby. Functional group interconversion can be used in retrosynthetic analysis to plan organic synthesis. A functional group is a group of atoms in a molecule with distinctive chemical properties, regardless of the other atoms in the molecule.

  7. 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 ...

  8. Period (periodic table) - Wikipedia

    en.wikipedia.org/wiki/Period_(periodic_table)

    Hydrogen readily loses and gains an electron, and so behaves chemically as both a group 1 and a group 17 element. Hydrogen (H) is the most abundant of the chemical elements, constituting roughly 75% of the universe's elemental mass. [1] Ionized hydrogen is just a proton. Stars in the main sequence are mainly composed of hydrogen in its plasma ...

  9. Biological roles of the elements - Wikipedia

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

    The remaining elements found in living things are primarily metals that play a role in determining protein structure. Examples include iron, essential to hemoglobin; and magnesium, essential to chlorophyll. Some elements are essential only to certain taxonomic groups of organisms, particularly the prokaryotes.