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Write the formula for Lithium Nitride. Agenda for Tuesday Jan 11 th Review/Practice Ionic Bonds Metallic Bonds Covalent bonds. Rules for writing Ionic formulas. The metal comes first (this does not include hydrogen), non-metal comes second. Find the oxidation number of each element
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Write the formula for Lithium Nitride. Agenda for Tuesday Jan 11th • Review/Practice Ionic Bonds • Metallic Bonds • Covalent bonds
Rules for writing Ionic formulas • The metal comes first (this does not include hydrogen), non-metal comes second. • Find the oxidation number of each element • The oxidation number of the metal becomes the subscript number of the non-metal and vise versa. Lithium nitride: Li1+ and N3- Li3N1 or Li3N
Rules for Naming Ionic formulas • Write the name of the positive ion (metal). • If you have a transition metal then you need to figure out its charge (remember the compound’s oxidation numbers must equal 0) and put it in roman numerals after the name; e.g. Copper (II). If it is not a transition metal proceed to step 3. • Write the root of the non-metal’s name (chlor- for chlorine, ox- for oxygen). • Add the ending –ide to the root.
Metallic Bonding • Composed of closely packed cations • Valence e- are a “sea of electrons” • Attraction between valence e- and cations
Metallic Bonding • “sea of electrons” model explains physical properties of metals • Good conductors – e- flow freely • Ductile • malleable • luster
Covalent Bonding • Nonmetal + nonmetal • share electrons • Can share more than one pair (double, triple bond) • Atoms held together by sharing electrons are covalently bonded
Covalent (Molecular) Bonds • Properties • Molecules • Lower melting and boiling points • Most are liq or gas • Nonconductors • Start to talk about shapes of molecules Ammonia molecule
Multiple Bonds • Double and triple covalent bonds • Sharing more than one pair of e- Carbon dioxide Nitrogen • Triple bonds are stronger than double bonds • More energy needed to break 3 bonds than 2 bonds
Polar and Nonpolar • Covalent bonding can be: • Polar – electrons not shared equally • Nonpolar – electrons shared equally
Drawing Covalent Compounds • Draw Dot structure for each compound • Pair unpaired electrons of each compound • Draw a line where you paired electrons
Naming Covalent Compounds • 1st word: Give the prefix designating the number of atoms of the first element present, then write the element’s name. • 2nd word: Give the prefix designating the number of atoms of the second element present. • CO2: carbon di • Name the root of the second element. • CO2: carbon diox • Add –ide to the root of the second element. • CO2: carbon dioxide (official name)
Practice N2O4 PCl5 NO CCl4 SCl2 Dinitrogen Tetroxide Phosphorus Pentachloride nitrogen monoxide or nitrogen oxide Carbon Tetrachloride Sulfur Dichloride
More Practice Sulfur Hexafluoride Pentanitrogen Heptoxide Diodine tetrachloride Triastatine Octoxide Phosphorous Mononitride SF6 N5O7 I2Cl4 At3O8 PN
Bonding 100% ionic100% covalent polar covalent ionic and covalent NaCl NaNO3Cl2 KBrBr2