Chapter 6 test on Chemical Bonding
Students should know and be able to do the following:
1. Define: chemical bond, cation, anion, electronegativity, ionic bonding, covalent bonding, metallic bonding, molecular compound, polar covalent, non-polar covalent, bond energy, electron-dot notation, lewis structure, ionic compound, polyatomic ion, malleability, ductility, VSEPR theory, intermolecular forces, dipole forces, hydrogen bonding, london forces.
2. The octet rule requires that all atoms have a full outer shell of electrons to be stable (8 for all atoms except H & He which only need 2).
3. Know that ionic bonds form when a non metal with high electronegativity takes an electron from a metal (the metal transfers the electron to the non-metal), forming ions, which pack together into very strong rigid solid crystals at room temperature.
4. Ionic compounds are non conductive solids that typically dissolve well in water. When dissolved or melted they do conduct well, however they are typically difficult to melt (HIGH melting and boiling points)
5. The positive ion(cation) is a metal. The negative ion(anion) can be a single non metal or a group of non metals covalently bonded together that need electrons to become stable (when they gain electrons they become anions).
6. Covalent compounds form when two or more non metals, with the same or similar electronegativites share electrons to form individual molecules (nickname: molecular compounds). The non metal atoms will share 2 electrons (single bond), four electrons (double bond) or six electrons (triple bond). The shorter the bond, the harder it is to break. The harder the bond is to break, the higher the "bond" energy needed to break it.
7. Because covalent compounds exist as individual molecules, they are typically gases or liquids at room temperature with low melting and boiling points, unless they have significant "intermolecular forces" between molecules such as hydrogen bonding or strong dipole-dipole forces. Even the gases and liquids will have weaker london forces drawing particles together.
8. Know how to draw a Lewis Structure.
9. Know how to determine molecular shape using VSEPR. (Lewis structure required)
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