1 Chapter 5 Ionic Compounds 5.1 Valence Electrons and Electron-Dot Symbols Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

2 Valence Electrons Valence electrons are The electrons in the electron configuration that are in the highest energy level Related to the group number

3 Electron Configurations and Valence Electrons

4 Electron-Dot Symbols An electron-dot symbol shows the valence electrons around the symbol of the element. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

5 Electron-Dot Symbols The electron-dot symbol for Mg shows two valence electrons as single dots on the sides of the symbol Mg... ·Mg · or Mg · or ·Mg or ·Mg · Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

6 Writing Electron-Dot Symbols Electron-dot symbols for: Groups 1A(1) to 4A(14) use single dots. · · Na · · Mg · · Al · · C · · Groups 5A(15) to 8A(18) use pairs and single dots. · · · · · P · : O · · ·

7 Groups and Electron-Dot Symbols In a group, all the electron-dot symbols have the same number of valence electrons (dots). Example: Group 2A(2) (2 valence electrons) · Be · · Mg · · Ca · · Sr · · Ba ·

8 Periodic Table and Electron-Dot Symbols Copyright © 2005 by Pearson Education, Inc Publishing as Benjamin Cummings

9 A. X is the electron-dot symbol for: 1) Na2) K3) Al B. X is the electron-dot symbol for: 1) B2) N3) P Learning Check

10 A. X is the electron-dot symbol for: 1) Na2) K B. X is the electron-dot symbol for: 2) N3) P Solution