Structure 2 / IB Chemistry / Structure 2.2 (lesson / Worksheets / Tests/ Tables / Figures)

Structure 2 / IB Chemistry / Structure 2.2 (lesson / Worksheets / Tests/ Tables / Figures)

Structure 2.2—The covalent model

Structure 2.2.1—A covalent bond is formed by the electrostatic attraction between a shared pair of electrons and the positively charged nuclei.

Structure 2.2.2—Single, double and triple bonds involve one, two and three shared pairs of electrons respectively.

Structure 2.2.3—A coordination bond is a covalent bond in which both the electrons of the shared pair originate from the same atom.

Structure 2.2.4—The valence shell electron pair repulsion (VSEPR) model enables the shapes of molecules to be predicted from the repulsion of electron domains around a central atom.

Structure 2.2.5—Bond polarity results from the difference in electronegativities of the bonded atoms.

Structure 2.2.6—Molecular polarity depends on both bond polarity and molecular geometry.

Structure 2.2.7—Carbon and silicon form covalent network structures.

Structure 2.2.8—The nature of the force that exists between molecules is determined by the size and polarity of the molecules. Intermolecular forces include London (dispersion), dipole-induced dipole, dipole–dipole and hydrogen bonding.

Structure 2.2.9—Given comparable molar mass, the relative strengths of intermolecular forces are generally: London (dispersion) forces < dipole–dipole forces < hydrogen bonding.

Structure 2.2.10—Chromatography is a technique used to separate the components of a mixture based on their relative attractions involving intermolecular forces to mobile and stationary phases.