Outline for Today Monday, Nov. 5 Chapter 7: Periodic Trends - PowerPoint PPT Presentation

Outline for Today Monday, Nov. 5 • Chapter 7: Periodic Trends • Ionization Energy • Electron A ffi nity • Exceptions to Trends and Electron Configurations • Chapter 8 • Ionic Bonding

Table 7.2: Ionization Energy

Successive Values of Ionization Energies Increase Element I 1 (kJ/mol) I 2 (kJ/mol) I 3 (kJ/mol) I 4 (kJ/mol) Na 496 4562 Mg 738 1451 7733 Al 578 1817 2745 11577 Si 786 1577 3232 4356

First Ionization Energy

Writing Electron Configurations of Cations • What is the electron configuration of: • Mg + • In 3+ • Ti 2+

What about Ions formed from Atoms with Unusual Electron Configurations? • What is the electron configuration of Ag + ? • How many unpaired electrons does Ag + have?

Some Exceptions to Electron Configuration Rules Electron Electron Element Element Configuration Configuration [Kr] 5s 1 4d 5 Mo Cr [Ar] 4s 1 3d 5 [Kr] 5s 1 4d 7 Ru Cu [Ar] 4s 1 3d 10 Rh [Kr] 5s 1 4d 8 Ag [Kr] 5s 1 4d 10 [Kr] 4d 10 Pd [Xe] 6s 1 4f 14 Au [Xe] 6s 1 4f 14 5d 9 Pt 5d 10

Back to Writing Electron Configurations of Ions! • What is the electron configuration of Ag + ? [Kr] 4d 10 How many unpaired electrons does Ag + have? None!

Electron Affinity

Exceptions to Ionization Energy Trends

Ionization Energy for the 2nd Row Elements

Exceptions to Radius Trends

Chapter 8: Basic Concepts in Chemical Bonding • Chemical Bond : When atoms or ions are strongly attracted. • Ionic Bond : Electrostatic forces (opposite charges) attract. Usually metal cations ionic bond to nonmetal anions. • Covalent Bond : Sharing of electrons, usually between nonmetals. • Metallic Bond : Each metal atom is bonded to many neighbors. Electrons are relatively free to move in the metal.

Valence Electrons form Bonds between Atoms • Lewis Electron Dot Symbols help us keep track of valence electrons. • Octet Rule : Atoms will tend to gain or lose electron to become isoelectronic with the nearest noble gas.

Ionic Bonding and Lattice Energy

Trends in Lattice Energy E electrostatic = κ Q 1 Q 2 d Li + : 0.9 Å Na + : 1.16 Å K + : 1.52 Å Cl - : 1.67 Å Rb + : 1.66 Å