Chemical Bonds Distinguish between common ionic and covalent compounds Construct chemical formulas for common compounds

Ions Elements want to have full valence electrons Na will lose one electron Chlorine will gain one electron Metals always lose electrons Nonmetals always gain electrons

Cations and anions Cations have positive charge Metals Valence electrons leave Na+ Ca 2+ Al 3+ Anions have negative charge Nonmetals Adds valence electrons Cl - O 2- N 3-

Ionic bonding Opposites attract Positive ions bond with negative ions http://en.wikipedia. org/wiki/File:NaF.gi f

Practice Draw the electron dot diagram of the atom Draw the electron dot diagram of the ion Draw the electron dot diagram of the compound H Cl Ba F Na S Do page 59-60

Covalent bonds Share electrons equally between atoms Between nonmetals http://bcs.whfreeman.com /thelifewire/content/chp02 /02020.html H:H H-H

Molecules Neutral group of atoms with one or more covalent bond Diatomic molecule-two atoms Can have single, double, or triple bond F—F O=O F2 O2 N2

Unequal sharing Polar molecules have unequal sharing of electrons One atom has more pull than the other

Equal sharing Non-polar molecules share electrons evenly Or electrons pulled in equal and opposite directions

Intermolecular forces Forces of attraction between molecules Molecules line up based on polarity Hydrogen bonds-weak bonds between hydrogen and a slightly negative molecule

Naming compounds Ionic compounds For the nonmetal Always name the metal first Then name the nonmetal If a transition metal, use Roman Numerals For the nonmetal Drop the ending and add –ide Fluorine—fluoride phosphorus—phosphide Oxygen—oxide nitrogen—nitride

Transition metals Transition metals can give multiple electrons Use roman numerals to tell you what the charge is Cu1+—copper (I) Cu2+--copper(II) Iron (II)—Fe2+ Iron (III)—Fe3+

Polyatomic ions Ammonium NH4- Carbonate CO32- Hydroxide OH- Phosphate Polyatomic ions have multiple atoms with a net charge Use parentheses and subscript to tell how many there are Ca(OH) 2 Na2SO3 Ammonium NH4- Carbonate CO32- Hydroxide OH- Phosphate PO43- Nitrate NO3- Acetate C2H3O2- Sulfate SO42- Permanganate MnO4-

Naming covalent molecules Write the name of the atom that is more to the left on the periodic table Hydrogen chloride HCl Use prefixes to tell how many there are Dihydrogen sulfide H2S Carbon monoxide CO Phosphorus pentafluoride PF5

Structure of Metals Metallic Bonds Lattice Properties Bonds between cations and free electrons Lattice Electrons move between and around the cations Sea of electrons Properties Carrying electrical current Conducting heat Flexibility Ductility

Alloys Alloy Metallic Properties Steel Copper A homogeneous mixture of two or more elements Metallic Properties Properties of metals Can change based on amount of one element over another Steel Carbon and iron Stainless steel has chromium Copper Bronze-copper and tin Brass