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Chemistry Chapter 8
Chemistry Chapter 8 Final Exam Review Covalent Bonding
Question | Answer |
---|---|
What info. does a molecular formula provide? | shows how many atoms of each element a substance contains |
What are the representative units for molecular compounds? | molecules |
What are the representative units for ionic compounds? | formula units |
What is the result of sharing electrons in covalent bonds? | atoms achieve configurations of noble gases (full octet of electrons) |
How are resonance structures used? | used to envision bonding in molecules that cannot be adequately described by a single structural formula |
How does VSEPR theory predict the shape of molecules? | VSEPR (valence shell electron pair repulsion theory) causes electron clouds to repel and spread out as far away from each other as possible. |
How is orbital hybridization useful in describing molecules? | it provides info. about both molecular bonding and molecular shape |
How do electronegativity values determine the charge distribution in a polar molecule? | the more electronegative atom attracts electrons more strongly and acquires a slightly negative charge |
How do the strengths of covalent, ionic, and intermolecular attractions compare? | ionic is strongest (electrostatic attraction between + & -), covalent is second (sharing e- to get octet) and intermolecular attractions are weakest |
Why are the properties of covalent compounds so diverse? | they are diverse due to widely varying intermolecular attractions |
What is a covalent bond? | atoms held together by sharing electrons, "tug of war" for electrons between atoms |
What is a molecule? | neutral group of atoms joined together by covalent bonds |
What is a diatomic molecule? | molecule containing exactly 2 atoms |
What is a polyatomic ion? | tightly bound group of atoms that has a positive or negative charge and behaves as a unit |
What is a polar covalent bond? | bond in which electrons are NOT shared equally |
What is a nonpolar covalent bond? | bond in which electrons are shared equally |
What are van der Waals forces? | 2 weakest attractions between molecules (dipole interactions and dispersion forces) |
What are dispersion forces? | weakest of all intermolecular attractions, caused by the motion of electrons, occur when electrons move around and influence neighboring molecule |
What is a hydrogen bond? | attractive forces in which a hydrogen covlanetly bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom. |
What is a network solid? | solids in which all of the atoms are covalently bonded to each other |
What is bond dissociation energy? | the energy required to break the bond between two covalently bonded atoms |