3.1 Introduction to Bonding Bonding is the joining of two atoms in a stable arrangement. Elements will gain, lose, or share electrons to reach the electron configuration of the noble gas closest to them in the periodic table. There are two different kinds of bonding: Ionic bonds result from the transfer of electrons from one element to another. Covalent bonds result from the sharing of electrons between two atoms.

3.1 Introduction to Bonding Ionic bonds form between: A metal on the left side of the periodic table. A nonmetal on the right side of the periodic table.

3.1 Introduction to Bonding Covalent bonds are formed when two nonmetals combine, or when a metalloid bonds to a nonmetal. A molecule is a compound or element containing two or more atoms joined together with covalent bonds. Covalent bonds and molecules will be discussed in more detail in Chapter 4.

Predict the bond type CO CaF2 MgO Cl2 HF C2H6

3.2 Ions A. Cations and Anions Ions are charged species in which the number of protons and electrons in an atom is unequal. Ionic compounds consist of oppositely charged ions that have a strong electrostatic attraction for each other. There are two types of ions—cations and anions.

3.2 Ions A. Cations and Anions Cations are positively charged ions.

3.2 Ions A. Cations and Anions the magnesium atom the magnesium ion

3.2 Ions A. Cations and Anions Anions are negatively charged ions. the chlorine atom the chlorine ion

3.2 Ions A. Cations and Anions Metals, like sodium (Na) and magnesium (Mg), form cations. Nonmetals, like chlorine (Cl), form anions. The octet rule: a main group element is especially stable when it possesses an octet of e− in its outer shell. octet = 8 valence e−

3.2 Ions B. Relating Group Number to Ionic Charge for Main Group Elements Elements in the same group form ions of similar charge. For metals in groups 1A, 2A, and 3A, the group number = the charge on the cation. For nonmetals in Groups 6A and 7A, the anion charge = 8 – the group number.

3.2 Ions B-1 Relating Group Number to Ionic Charge for Groups 1A–3A the cation charge = the group number group 1A: group 2A: group 3A:

3.2 Ions B-2 Relating Group Number to Ionic Charge for Groups 6A and 7A the anion charge = 8 – group number group 6A: group 7A:

3.2 Ions C. Metals with Variable Charge

How many protons and electrons do the following ions have? N-3 7. Br- O-2 8. B+3 Li+1 9. As-3 K+1 Ga+3 Mg+2

3.3 Ionic Compounds An ionic bond is formed when a metal transfers one or more electrons to a nonmetal.

3.3 Ionic Compounds

HOW TO Write a Formula for an Ionic Compound 3.3 Ionic Compounds HOW TO Write a Formula for an Ionic Compound Identify which element is the cation and which is the anion. Step [1] Metals form cations and nonmetals form anions. Use the group number of a main group element to determine the charge. K+ K Cl− Cl Ca2+ Ca O2− O

HOW TO Write a Formula for an Ionic Compound 3.3 Ionic Compounds HOW TO Write a Formula for an Ionic Compound Determine how many of each ion type is needed for an overall charge of zero. Step [2] When the cation and anion have the same charge, only one of each is needed. K+ + Cl− Ca2+ + O2−

HOW TO Write a Formula for an Ionic Compound 3.3 Ionic Compounds HOW TO Write a Formula for an Ionic Compound When the cation and anion have different charges, use the ion charges to determine the number of ions of each needed. Ca2+ Cl−

What’s the formula of the ionic compound made by bonding the following pairs? Li + Br Cl + O Ca + Mg B + Cl Li + O Ga + S

3.4 Naming Ionic Compounds A. Naming Cations Main group cations (groups 1—3A) are named for the element from which they are formed. Na+ K+ Ca2+ Mg2+

3.4 Naming Ionic Compounds A. Naming Cations When a metal is able to form two different cations: Follow the name of the cation by a Roman numeral in parentheses to indicate its charge. Fe2+ Fe3+

3.4 Naming Ionic Compounds A. Naming Cations

3.4 Naming Ionic Compounds B. Naming Anions Anions are named by replacing the ending of the element name by the suffix “-ide.”

3.4 Naming Ionic Compounds C. Compounds of Main Group Metals Name the cation and then the anion. Do not specify the charge on the ion. Do not specify how many ions of each type are needed to balance charge. Na+ sodium + F− fluoride NaF sodium fluoride Mg2+ magnesium + Cl− chloride MgCl2 magnesium chloride

3. 4. Naming Ionic Compounds D 3.4 Naming Ionic Compounds D. Compounds of Metals with a Variable Charge HOW TO Name an Ionic Compound That Contains a Metal with Variable Charge Example Give the name for CuCl2. Step [1] Determine the charge on the cation.

3. 4. Naming Ionic Compounds D 3.4 Naming Ionic Compounds D. Compounds of Metals with a Variable Charge HOW TO Name an Ionic Compound That Contains a Metal with Variable Charge Step [2] Name the cation and the anion. The cation is named followed by its charge in parenthesis: Cu2+ The anion changes ending of element name to “-ide” Cl−

3. 4. Naming Ionic Compounds D 3.4 Naming Ionic Compounds D. Compounds of Metals with a Variable Charge HOW TO Name an Ionic Compound That Contains a Metal with Variable Charge Write the name of the cation first, then the anion. Step [3] Answer =

Give the symbol or name for the following ions S-2 7. Iodide Cs+1 8. Fluoride Sn+4 9. Lead (II) Cu+1 10. Tin (IV) Al+3 11. Chloride Fe+2 12. Sulfide

3.4 Naming Ionic Compounds E. Writing a Formula from the Name HOW TO Derive a Formula from the Name of an Ionic Compound Example Write the formula for tin(IV) oxide. Step [1]

3.4 Naming Ionic Compounds E. Writing a Formula from the Name HOW TO Derive a Formula from the Name of an Ionic Compound Step [2] Balance charges. Write the formula with the cation first, and use subscripts to show how many of each ion is needed to have zero overall charge. Step [3]

Give the oxidation state and formal name for the following copper ions: Cu2O (brown) CuO (black) CuCl (green) CuCl2 (blue)

Give the oxidation state and formal name for the following ions: CrCl3 PbS SnF4 PbO2 AuCl3 Na2O

Give the formula for the following ions Chromium (III) Chloride Tin (IV) Fluoride Magnesium Sulfide Lead (II) Sulfide Lead (IV) Oxide Gold (III) Chloride

3.6 Polyatomic Ions A polyatomic ion is a cation or anion that contains more than one atom.

3.6 Polyatomic Ions A. Writing Formulas for Ionic Compounds with Polyatomic Ions Same as ions with single charged atoms. (Section 3.3A) Na+ + NO2− Ba2+ + SO42−

3.6 Polyatomic Ions A. Writing Formulas for Ionic Compounds with Polyatomic Ions When a cation and anion of unequal charge combine, use the ionic charges to determine the relative number of each ion that is needed. Mg2+ + OH−

Write the charge and formula for the following ions K + OH K + NO2 Mg + HSO3 Ba + OH K + PO4 Ca + CN

3.6 Polyatomic Ions B. Naming Ionic Compounds with Polyatomic Ions The same rules are followed for naming standard ionic compounds: Name the cation and then the anion. Do not specify the charge on the ions. Do not specify how many ions of each type are needed to balance charge. NaHCO3 Al2(SO4)3

Name the following molecules Na2CO3 Ca(OH)2 Mg(NO3)3 Mn(CH3CO2)2 Fe(HSO3)3 Mg(PO4)2

Exam 1 Review W = Fe = Mg = Au = Ag = F = U =

Sig Figs 1.2348 + 1.86 = 1.24987654321 – 0.02 = (3.212)x(4.102) = (8.2) / (10.19) =

Bonding N2 O2 H2O MgCl2 Mg(OH)2 NaCl

Electron Dot Structures Mg As Br Kr

Charges K Ca B Br Sr S F Na

Noble Gas Notation [Xe] 6s24f9 [Ar] 4s23d8 [Ne] 3s23p4 1s22s22p63s23p4 [Xe] 6s24f145d4 [Rn] 7s25f4

Name the following NaCl MgCl2 AuCl2 FeBr3 PbBr2 CuO

Give the formula Lithium Nitrite Calcium Hydroxide Magnesium Sulfite Potassium Sulfate Aluminum Nitrate Calcium Acetate Boron Phospate

Fill in the Table Br PO42- CO32- -OH K Na Mg H