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  2. Ball-and-stick model - Wikipedia

    en.wikipedia.org/wiki/Ball-and-stick_model

    These models allowed rotation about the single rod bonds, which could be both an advantage (showing molecular flexibility) and a disadvantage (models are floppy). The approximate scale was 5 cm per ångström (0.5 m/nm or 500,000,000:1), but was not consistent over all elements.

  3. Group 13/15 multiple bonds - Wikipedia

    en.wikipedia.org/wiki/Group_13/15_multiple_bonds

    Heteroatomic multiple bonding between group 13 and group 15 elements are of great interest in synthetic chemistry due to their isoelectronicity with C-C multiple bonds. . Nevertheless, the difference of electronegativity between group 13 and 15 leads to different character of bondings comparing to C-C multip

  4. Coordination number - Wikipedia

    en.wikipedia.org/wiki/Coordination_number

    The ion/molecule/atom surrounding the central ion/molecule/atom is called a ligand. This number is determined somewhat differently for molecules than for crystals. For molecules and polyatomic ions the coordination number of an atom is determined by simply counting the other atoms to which it is bonded (by either single or multiple bonds). [1]

  5. Lewis structure - Wikipedia

    en.wikipedia.org/wiki/Lewis_structure

    A trick is to count up valence electrons, then count up the number of electrons needed to complete the octet rule (or with hydrogen just 2 electrons), then take the difference of these two numbers. The answer is the number of electrons that make up the bonds. The rest of the electrons just go to fill all the other atoms' octets.

  6. Chemical structure - Wikipedia

    en.wikipedia.org/wiki/Chemical_structure

    Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together and can be represented using structural formulae and by molecular models; [1] complete electronic structure descriptions include specifying the occupation of a molecule's molecular orbitals.

  7. Lone pair - Wikipedia

    en.wikipedia.org/wiki/Lone_pair

    Thus, the number of electrons in lone pairs plus the number of electrons in bonds equals the number of valence electrons around an atom. Lone pair is a concept used in valence shell electron pair repulsion theory (VSEPR theory) which explains the shapes of molecules. They are also referred to in the chemistry of Lewis acids and bases. However ...

  8. Group (periodic table) - Wikipedia

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

    In the periodic table of the elements, each column is a group. In chemistry, a group (also known as a family) [1] is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table; the 14 f-block columns, between groups 2 and 3, are not numbered.

  9. Period (periodic table) - Wikipedia

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

    In the f-block and p-block of the periodic table, elements within the same period generally do not exhibit trends and similarities in properties (vertical trends down groups are more significant). However, in the d-block, trends across periods become significant, and in the f-block elements show a high degree of similarity across periods.