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Chapter 8: Covalent Bonding Resources: Chapter 8 of our TB and unit 6 of workbook Ch. 8 reading and study guide (in part) Powerpoint used in class Lab practical: Molecular models Handouts: practice problems and naming of covalent/molecular compounds Animations and simulation.
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Chapter 8: Covalent Bonding • Resources: • Chapter 8 of our TB and unit 6 of workbook • Ch. 8 reading and study guide (in part) • Powerpoint used in class • Lab practical: Molecular models • Handouts: practice problems and naming of covalent/molecular compounds • Animations and simulation • Simulations and animations: • Ionic and covalent bonding animation: http://www.youtube.com/watch?v=QqjcCvzWwww • Animation and song: what kinds of bonds are these: • http://www.youtube.com/watch?v=oNBzyM6TcK8 • Mark Rosengarten video tutorials on polarity of molecules: • http://www.youtube.com/watch?v=mtRgeBSe1o8&feature=related • glencoe animations and interactive lesson: • http://glencoe.mcgraw-hill.com/sites/0078807239/student_view0/chapter9/concepts_in_motion.html# • Animation: Ionic compounds versus nonpolar and polar molecules • Properties of ionic and covalent compounds:
8.1 Molecules and Molecular Compounds • In nature, matter takes many forms. The noble gases, including helium and neon, are monatomic. That means they exist as single atoms. • Represented by symbols: He, Ne, etc) • the noble gases are not molecules
8.1 Molecules and Molecular Compounds • A molecule is a neutral group of atoms joined together by covalent bonds. Air contains oxygen molecules. • A diatomic molecule is a molecule consisting of two atoms. An oxygen molecule is a diatomic molecule.
8.1 Molecules and Molecular Compounds • Some elements do exist as diatomic molecules. • Hydrogen H2 (g) • Oxygen O2 (g) • Fluorine F2 (g) • Bromine Br2 (l) • Iodine I2 (s) • Nitrogen N2 (g) • Chlorine Cl2 (g)
8.1 Molecules and Molecular Compounds • Pneumonic device to remember those elements that exist in nature as diatomic molecules.? (HOFBrINCl) • (write out symbols, add 2 as a subscript) H O F Br I N Cl H2 O2 F2 Br2 I2 N2 Cl2 • (note these are molecules but they are not compounds)
8.1 Molecules and Molecular Compounds • A compound composed of molecules is called a molecular compound. Water and carbon monoxide are molecular compounds.
8.1 Molecular Formulas • Formulas of Some Molecular Compounds
8.1 Molecules and Molecular Compounds
8.1 Molecular Formulas • A molecular formula is the chemical formula of a molecular compound. • A molecular formula shows how many atoms of each element a molecule contains.
8.1 Molecular Formulas
8.1 Molecules and Molecular Changes • Ethane, a component of natural gas, is also a molecular compound.
Types of Bonding ? (review) • Chapter 8: Covalent Bonding
Sea of electrons model used to explain bonding in metals • Kernel & delocalized mobile valence electrons BONDING
Electrostatic attraction of negatively and positively charged ions Can be formed as a result of the transfer of electrons between metal and nonmetal atoms to form cations and anions BONDING
Bonding in: Na ? NaCl? H2 or Cl2 ? HCl ? H2O ?
8.1 Molecules and Molecular Compounds • Molecules and Molecular Compounds • How are the melting points and boiling points of molecular compounds different from those of ionic compounds?
8.1 Molecules and Molecular Changes • Molecular compounds tend to have relatively lower melting and boiling points than ionic compounds.
Practice – properties of ionic and covalent compounds • Go to interactive table on Glencoe site: Physical Properties of ionic and covalent compounds • http://glencoe.mcgraw-hill.com/sites/0078807239/student_view0/chapter9/concepts_in_motion.html#
8.1 Section Quiz. • 8.1.
8.1 Section Quiz. • 1. Compared to ionic compounds, molecular compounds tend to have relatively • low melting points and high boiling points. • low melting points and low boiling points. • high melting points and high boiling points. • high melting points and low boiling points.
8.1 Section Quiz • 2. A molecular compound usually consists of • two metal atoms and a nonmetal atom. • two nonmetal atoms and a metal atom. • two or more metal atoms. • two or more nonmetal atoms.
8.1 Section Quiz • 3. A molecular formula shows • how many atoms of each element a molecule contains. • a molecule's structure. • which atoms are bonded together. • how atoms are arranged in space.