4: Molecular Compounds
- Page ID
- 86208
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- 4.1: Covalent Bonds
- You have already seen examples of substances that contain covalent bonds. One substance mentioned previously was water (H₂O). You can tell from its formula that it is not an ionic compound; it is not composed of a metal and a nonmetal. Consequently, its properties are different from those of ionic compounds. A covalent bond is formed between two atoms by sharing electrons.
- 4.2: Covalent Bonds and the Periodic Table
- Atoms share electrons and form covalent bonds to satisfy the octet rule. The periodic table and trends in valence electrons can be used to determine the number of bonds an atom is most likely to form.
- 4.3: Multiple Covalent Bonds
- Some molecules must have multiple covalent bonds between atoms to satisfy the octet rule.
- 4.4: Coordinate Covalent Bonds
- Each of the covalent bonds that we have looked at so far has involved each of the atoms that are bonding contributing one of the electrons to the shared pair. There is an alternate type of covalent bond in which one of the atoms provided both of the electrons in a shared pair.
- 4.5: Characteristics of Molecular Compounds
- Ionic compounds and molecular compounds have very different physical properties.
- 4.6: Molecular Formulas and Lewis Structures
- Molecules can be represented using formulas, which give information about the number and type of atoms bonded together. Different types of structural formulas show the bonds between atoms and sometimes give information about molecular shape as well.
- 4.7: Drawing Lewis Structures
- Molecules can be represented using Lewis structures, which show how electrons are arranged around the atoms in a molecule as bonded pairs of electrons (bonds) and lone pairs of electrons. These structures are useful for explaining and depicting molecular shapes and chemical reactivity.
- 4.8: The Shapes of Molecules
- According to valence-shell electron-pair repulsion theory, VSEPR, the electron groups minimize repulsion by getting as far apart as possible from each other. Therefore, the approximate shape of a molecule can be predicted from the number of electron groups and the number of surrounding atoms.
- 4.9: Polar Covalent Bonds and Electronegativity
- Covalent bonds between different atoms have different bond lengths. Covalent bonds can be polar or nonpolar, depending on the electronegativity difference between the atoms involved.
- 4.10: Polar Molecules
- The molecular polarity of a diatomic molecule is determined by the bond polarity. The polarity of molecules with more than one bond must be determined by first identifying the molecular structure and then the bond polarity. If the dipole moments point in a similar direction, there is a net molecular dipole. If the dipole moments point in opposite directions, they cancel out and there is no net dipole.
- 4.11: Naming Binary Molecular Compounds
- The chemical formula of a simple covalent compound can be determined from its name. The name of a simple covalent compound can be determined from its chemical formula.
Thumbnail: Covalently bonded hydrogen and carbon in a w:molecule of methane. (CC BY-SA 2.5; DynaBlast via Wikipedia)