Ionic Bonding and Ionic Compounds Chapter 6 and 15 Ionic Bonding and Ionic Compounds

Ionic vs. Molecular What is a molecule? A molecule is the smallest electrically neutral unit of a substance that still has the properties of that substance. Molecules are made up of 2 or more atoms that act as a unit.

Ionic vs Molecular: Can we describe the smallest electrically neutral unit of an ionic compound as a molecule? Can we describe NaCl as a molecule?

Chemical Bonds Revisited: An electrostatic force of attraction between two atoms, ions, or molecules

Why do Atoms Bond? Octet Rule: Atoms will lose, gain, or share electrons to achieve a stable octet. Stable Octet: 8 valence electrons or a noble gas configuration.

Chemical Bonding Atoms within the same group of the periodic table have the same number of valence electrons. Valence electrons determine the chemical properties of an element

Valence electrons revisited: Valence electrons are usually the only electrons used in chemical bonds.

Valence electrons How do you determine the number of valence electrons? The group number The electron configuration diagram

Ions: Particles that have either gained or lose electrons. Metals lose electrons to make positive ions Nonmetals gain electrons to make negative ions.

Ionic Compounds (Formula Unit) Ionic compounds do not exist as molecules Ionic compounds exist as a collection of positively and negatively charged ions arranged in repeating 3-D patterns

Ionic Bonds Ionic Bonds: Bonds formed between positive and negative ions (metals and nonmetals)

Properties of ionic compounds Crystalline Solids

Properties of ionic compounds Electrolytes: Conduct electricity when dissolved in water Conduct electricity in the liquid state but not the solid state High Melting points and Boiling points

Shows the numbers and types of atoms present in a chemical compound. Chemical Formula Shows the numbers and types of atoms present in a chemical compound.

Formula Unit: Used to represent an Ionic compound (no molecules) Lowest whole number ratio of ions in an ionic compound Examples: MgCl2, KBr, AlF3

Monatomic Ions: Ions consisting of one atom Monatomic cations Sodium( Na+), lithium (Li+), Calcium (Ca2+), Aluminum (Al 3+) Monatomic anions Fluoride (F-), Oxide (O2-), Phosphide (P3-)

Ionic Charges: Stock system: For naming cations with more than one possible charge Example: Iron Has two possibilities (II), (III) Written as Iron(II) ion (Fe2+) and Iron(III) ion (Fe3+)

Ionic Charges: Can also use the root word with a different suffix to designate between multiple charged cations: Example: Iron(II): ferrous (Fe2+) Iron(III): ferric (Fe3+)

Ionic Charges Polyatomic ions: More than one atom Tightly bound groups Behave as one unit

Ionic Charges: Polyatomic ions: Most end in –ite, or –ate Exceptions: Ammonium (NH4+) Hydroxide (OH-) Cyanide (CN-)

Ionic Charges: Polyatomic ions with hydrogen: Example: HCO3- Note: the charge of the new ion is the sum of the charges of the composite ions

Common Polyatomic Ions 1- charge 2- charge 3- charge Formula Name H2PO4- Dihydrogen phosphate HPO42- Hydrogen phosphate PO33- Phosphite C2H3O2- Acetate C2O42- Oxalate PO43- Phosphate HSO3- Hydrogen sulfite SO32- Sulfite HSO4- Hydrogen sulfate SO42- Sulfate HCO3- Hydrogen carbonate CO32- Carbonate 1+ charge NO2- Nitrite Cr2O42- Chromate NO3- Nitrate Cr2O72- Dichromate NH4+ Ammonium CN- Cyanide SiO32- Silicate OH- Hydroxide MnO4- Permanganate ClO- Hypochlorite ClO2- Chlorite ClO3- Chlorate ClO4- Perchlorate 22

Nick the Camel ATE a Clam for Supper in Phoenix Trick for remembering –ate ions… Nick the Camel ATE a Clam for Supper in Phoenix Underlined letter represents the symbol of the element The #of consonants = the # of oxygen atoms The # vowels = charge EX: Nick = nitrogen N = nitrogen 3 consonants = 3 oxygens 1 vowel = -1 charge Nitrate = NO3-

Nick the Camel ATE a Clam for Supper in Phoenix Trick for remembering –ate ions… Nick the Camel ATE a Clam for Supper in Phoenix EX: Camel C = carbon 3 consonants = 3 oxygens 2 vowel = -2 charge carbonate = CO3-2

Nick the Camel ATE a Clam for Supper in Phoenix Trick for remembering –ate ions… Nick the Camel ATE a Clam for Supper in Phoenix EX: Clam Cl = chlorine 3 consonants = 3 oxygens 1 vowel = -1 charge chlorate = ClO3-1

Nick the Camel ATE a Clam for Supper in Phoenix Trick for remembering –ate ions… Nick the Camel ATE a Clam for Supper in Phoenix EX: Supper S = sulfur 4 consonants = 4 oxygens 2 vowel = -2 charge sulfate = SO4-2

Nick the Camel ATE a Clam for Supper in Phoenix Trick for remembering –ate ions… Nick the Camel ATE a Clam for Supper in Phoenix EX: Phoenix P = phosphate 4 consonants = 4 oxygens 3 vowel = -3 charge phosphate = PO4-3

Binary Ionic Compounds: Compounds that are composed of two elements Electrically neutral (net charge of zero Ionic Binary compounds are composed of a 1. Cation (+) always written first 2. Anion (-) always written last Examples: KCl NaCl CaBr2

Bionary Ionic Compounds Writing a balanced formula- Criss Cross Method Must first find identify charges of ions Find least common multiple Example: write the formula for Iron (III) Oxide Calcium Sulfide Alumimum Chloride

Naming Binary Ionic Compounds 1. write the name of the metallic cation ion. Use the stock naming system 2. then write the name of the non-metallic anion. Examples: CuO MgCl2 SnO2

Ternary Ionic Compounds A compound that contains atoms of three different elements Involves polyatomic ions – usually polyatomic anions Writing the formula for ternary compounds is the same as binary compounds (criss cross method) Naming ternary ionic compounds- see Nick the Camel etc…

Acids: Acids are a special group of compounds that release hydrogen ion in solution When naming, can consider them as ionic compounds (cations and anions) Hydrogen = cation Monatomic or polyatomic anion

Naming Acids If the anion = monatomic- Start with –hydro (prefix) drop –ide and add –ic. (root word) Example: HCl H = hydro Cl = chloride  chloric HCl = hydrochloric acid

Naming Acids If the anion = polyatomic- No -hydro If –ate, drop –ate and add –ic. (root word) If – ite, drop –ite and add – ous (root word)

Naming Acids Example: H2SO4 SO4 = sulfate- drop –ate and add –ic Add – acid Sulfuric Acid Example: H2SO3 SO3 = Sulfite – drop –ite and add –ous Add – acid Sulfurous Acid

Chapter 15 Electron Configuration in Ionic Bonding

Electron Configuration in Ionic Bonding: Cations Cations(metals) will lose electrons to fulfill their octet. Examples: Sodium Potassium Calcium Aluminum

Electron Configuration in Ionic Bonding: Anions Anions or non-metals will accept electrons to fulfill their octet. Fluorine Oxygen Nitrogen Bromide

Formation of Ionic Compounds: Electrostatic forces of attraction Attraction of opposite charges Electrically neutral Total positives = total negatives Combine in whole number ratios to satisfy the octet Examples: NaCl Al2O3 MgCl2

Coordination Number: Number of ions of opposite charge that surround the ion in a crystal Ionic compounds have a crystalline structure 3-D arrangement of alternating positively and negatively charged particles Example: NaCl Coordination number of Na = 6 Coordination number of Cl = 6