The Octet Rule Atoms tend to gain, lose, or share electrons until they have eight valence electrons. 8 Valence Electrons - Outermost electrons on the outermost shell/energy level Valence electrons are the available electrons for bonding. The Group number tells you the number of valence electrons. OCTET RULE Rule in which all elements want to satisfy. All elements want to have a full or empty outermost shell/energy level. They want to have 8 valence electrons to become stable.

Atomic Structure ATOMSATOMS –Differ by number of protons ISOTOPESISOTOPES –Differ by number of neutrons IONSIONS –Differ by number of electrons

Formation of Cation 11p + sodium atom Na e-e- loss of one valence electron e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- sodium ion Na + 11p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

Formation of Anion 17p + chlorine atom Cl e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- gain of one valence electron chloride ion Cl 1- 17p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

Formation of Ionic Bond chloride ion Cl 1- sodium ion Na + 11p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- 17p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

Various Ions Zn 2+ Ag 1+ Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 74

Periodic Table with Group Names

Predicting Ionic Charges Group 1: Alkali Metals, 1 valence electron Lose 1 electron to form 1+ ions H 1+ Li 1+ Na 1+ K 1+

Predicting Ionic Charges Group 2: Alkaline Earth Metals, 2 valence e - Loses 2 electrons to form 2+ ions Be 2+ Mg 2+ Ca 2+ Sr 2+ Ba 2+

Predicting Ionic Charges Groups : Transition Metals Many transition elements have more than one possible oxidation state. Iron(II) = Fe 2+ Iron(III) = Fe 3+

Predicting Ionic Charges Group 13: Boron Group, 3 valence e - Loses 3 electrons to form 3+ ions B 3+ Al 3+ Ga 3+

Predicting Ionic Charges Group 14: Carbon Group, 4 valence e - Loses 4 electrons or gains 4 electrons (4±) C 4- Si 4+ Pb 4+

Predicting Ionic Charges Group 15: Nitrogen Group, 5 valence e - Gains 3 electrons to form 3- ions N 3- P 3- As 3- Nitride Phosphide Arsenide

Predicting Ionic Charges Group 16: Oxygen Group, 6 valence e - Gains 2 electrons to form 2- ions O 2- S 2- Se 2- Oxide Sulfide Selenide

Predicting Ionic Charges Group 17: Halogens, 7 valence e - Gains 1 electron to form 1- ions F 1- Cl 1- Br 1- Fluoride Chloride Bromide I 1- Iodide

Predicting Ionic Charges Group 18: Noble Gases, 8 valence e -, Except He which has 2 valence e INERT- Nonreactive, do not form ions! Full outermost energy level. Maximum number of valence electrons possible.

K2OK2O CaS NH 4 OH NaCl MgSO 4 Naming CompoundsNaming Compounds

First - write the name of the metal. (Cation) Name does not change Then - write the name of the nonmetal (Anion) with an -ide ending. Examples: NaCl - sodium chloride CaI 2 - calcium iodide Li 2 O - lithium oxide Ag 3 N – silver nitride Try These: MgS - ZnBr 2 - Al 2 O 3 - Fe 2 O 3 - Metal vs. Non-metal NamingMetal vs. Non-metal Naming Magnesium sulfide Zinc bromide Aluminum oxide Iron(III) oxide (rust)

First - write the name of the metal. (Cation) Then - write the name of the polyatomic ion WITHOUT changing its name. The prefix Poly- means “many” or “more than 1” Polyatomic ion – an ion that has more than one type of element, covalently bonded to each other yet it still contains a (+) or (-) charge. The only "positive" polyatomic ion used in this class is ammonium, NH 4 +. Examples: MgSO 4 - magnesium sulfate CaCO 3 - calcium carbonate NaOH - sodium hydroxide NH 4 NO 3 - ammonium nitrate Try These: KOH – Li 3 PO 4 – AgNO 3 – Al 2 (SO 4 ) 3 – Naming Polyatomic CompoundsNaming Polyatomic Compounds Potassium hydroxide Lithium phosphate Silver nitrate Aluminum sulfate

If the positive element has more than one possible oxidation number, or if it is out of character, its oxidation is shown as a Roman numeral in parentheses after its name. Examples: Fe 2 O 3 - Iron (III) oxide Fe 2 (SO 4 ) 3 – iron (III) sulfate CuCl - copper (I) chloride Pb (CO 3 ) 2 – lead (IV) carbonate Try These: HgI 2 – FeO – MnO – SnCl 2 – CrBr 3 – Roman NumeralsRoman Numerals mercury(II) iodide iron(II) oxide manganese (II) oxide tin(II) chloride chromium(III) bromide

Concept Review Naming CompoundsConcept Review Naming Compounds Concept Understanding: Write the correct name for each of these compounds: 1. Fe(OH) 2 2. (NH 4 ) 3 PO 4 3. AlPO 4 4. Cu(C 2 H 3 O 2 ) 2 5. CaCO 3 6. NH 4 OH 7. Cr 2 (SO 4 ) 3 8. Mg(NO 3 ) 2 Iron(II) hydroxide Ammonium phosphate Aluminum phosphate Copper(II) acetate Calcium carbonate Ammonium Hydroxide Chromium(III) sulfate Magnesium nitrate

“Perhaps one of you gentlemen would mind telling me just what is outside the window that you find so attractive..?” Image courtesy NearingZero.net

1.Write the oxidation number above each element. 2.Cross the oxidation numbers and write the oxidation number (without plus or minus) of one element as the subscript of the other element. 3.Reduce the subscripts (number of atoms) to their simplest form, if needed. Writing Chemical FormulasWriting Chemical Formulas WHAT IS THE CHEMICAL FORMULA FOR CALCIUM CHLORIDE?

1.Write the oxidation number above each element. 2.Cross these and write the oxidation number (without plus or minus charge) of one element as the subscript of the other element. 1+ LiO 2- Lithium oxide 2+ BaN 3- Barium Nitride 2+ Mg KCl 1- Magnesium Sulfide Potassium Chloride S = Li 2 O = Ba 3 N 2 = MgS = KCl Writing Formulas Continued…Writing Formulas Continued… 1+ NaI 1- Sodium Iodide = NaI

1.Write the oxidation number above each (putting parantheses around the polyatomic ion). 2.Cross these and write the oxidation number (without plus or minus charge) of each ion as the subscript of the other atom/polyatomic ion. 1+ Na(OH) 1- Sodium hydroxide 2+ Ca(CO 3 ) 2- Calcium carbonate 2+ Zn Al(NO 3 ) 1- Zinc phosphate Aluminum nitrate (PO 4 ) = NaOH = CaCO 3 = Zn 3 (PO 4 ) 2 = Al(NO 3 ) 3 Writing Formulas with polyatomic ionsWriting Formulas with polyatomic ions 1+ (NH 4 )(SO 3 ) 2- Ammonium sulfite = (NH 4 ) 2 SO 3

1. NaCl =Sodium Chloride 2. K 2 O = 3. CaF 2 = 4. Fe 2 O 3 = 5. CuCl = 6. NaOH = 7. AlPO 4 = 8. Mg(NO 3 ) 2 = Potassium Oxide Calcium Fluoride Iron (III) Oxide Copper (I) Chloride Sodium Hydroxide Aluminum Phosphate Magnesium Nitrate

Example: Aluminum Chloride Step 1: Step 2: Step 3: 13 Step 4: AlCl 3 Criss-Cross Rule Al Cl write out name with space write symbols & charge of elements criss-cross charges as subsrcipts combine as formula unit (“1” is never shown) Aluminum Chloride

Example: Aluminum Chloride Step 1: AluminumChloride Step 2: Al 3+ Cl 1- Step 3: Al Cl 13 Step 4: AlCl 3 Criss-Cross Rule

Example: Aluminum Oxide Step 1: Aluminum Oxide Step 2: Al 3+ O 2- Step 3: Al O 23 Step 4: Al 2 O 3 Criss-Cross Rule

Example: Magnesium Oxide Step 1: Magnesium Oxide Step 2: Mg 2+ O 2- Step 3: Mg O 22 Step 4: Mg 2 O 2 Step 5: MgO Criss-Cross Rule

Ionic Compounds: Formed from oppositely charged ions Cations: Positively charged ions (METALS) give e - away Anions: Negatively charged ions (NONMETALS) take e - in Positive ions (Cations) take the names of the metal from which they are derived: Na + = Sodium ion, Ca 2+ = Calcium ion, Al 3+ = Aluminum ion (The name DOES NOT CHANGE) Negative ions (Anions) are named by adding the suffix -ide to the stem of the name of the nonmetal from which they are derived: Cl - = Chloride ion, O 2- = Oxide ion, N 3- = Nitride ion (-ide is added to the end)

1. Cation (Metal) first, then Anion (Nonmetal) 2. Monatomic Cation = name of the element Ca 2+ = calcium ionCa 2+ = calcium ion Na + = sodium ionNa + = sodium ion Al 3+ = aluminum ionAl 3+ = aluminum ion 3. Monatomic Anion = root name + -ide Cl  = chlorideCl  = chloride O 2- = oxideO 2- = oxide CaCl 2 = calcium chlorideCaCl 2 = calcium chloride Na 2 O = sodium oxideNa 2 O = sodium oxide

When a metal forms more than one ion (as the transition metals do), it is necessary to distinguish between these ions. The accepted practice today is to indicate the charge of the ion by a ROMAN NUMERAL in (parentheses) immediately following the name of the metal. The following are the only metals with multiple ions you need to know: Fe 2+ = Iron (II)Fe 3+ = Iron (III) Hg + = Mercury (I)Hg 2+ = Mercury (II) Cu + = Copper (I)Cu 2+ = Copper (II) Mn 2+ = Manganese (II)Mn 3+ = Manganese (III) Pb 2+ = Lead (II)Pb 4+ = Lead (IV) Cr 2+ = Chromium (II)Cr 3+ = Chromium (III)

Polyatomic Ions – An ion consisting of a group of bonded atoms. Polyatomic ions have a suffix ending in –ate or –ite (except for OH - = hydroxide ion, NH 4 + = Ammonium) The difference in the polyatomic ending, is in the number of Oxygen atoms. Polyatomic ions with more Oxygen atoms will take on the –ate suffix. Sulfate = (SO 4 2- ) Nitrate (NO 3 - ) Polyatomic ions with less Oxygen atoms will take on the –ite suffix. Sulfite = (SO 3 2- ) Nitrite = (NO 2 - )