Chapter 5 Ionic Compounds Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

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

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

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

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

An octet Is 8 valence electrons Is associated with the stability of the noble gases He is stable with two valence electrons (duet). valence electrons He 1s 2 2 Ne 1s 2 2s 2 2p 6 8 Ar 1s 2 2s 2 2p 6 3s 2 3p 6 8 Kr 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 8 Octet Rule

Ionic and Covalent Bonds Atoms acquire octets To become more stable By losing, gaining, or sharing valence electrons By forming ionic bonds or covalent bonds Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Formation of a Sodium Ion, Na + Sodium achieves an octet by losing its one valence electron. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Formation of Mg 2+ Magnesium achieves an octet by losing its two valence electrons. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Learning Check A. Number of valence electrons in aluminum is: 1) 1e - 2) 2e - 3) 3e - B. Change in electrons for octet requires a: 1) loss of 3e - 2) gain of 3e - 3) a gain of 5e - C. Ionic charge of aluminum is: 1) 3-2) 5-3) 3 + D. The symbol for the aluminum ion is: 1) Al 3+ 2) Al 3- 3) Al +

Formation of a Chloride, Cl - Chlorine achieves an octet by adding an electron to its valence electrons. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

A. Number of valence electrons in sulfur is: 1) 4e - 2) 6e - 3) 8e - B. Change in electrons for octet requires a: 1) loss of 2e - 2) gain of 2e - 3) a gain of 4e - C. Ionic charge of sulfur is: 1) 2+ 2) 2- 3) 4- Learning Check

Examples of Ionic Charges

Sizes of Ions Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings The positive ions of metals are about half the size of the corresponding metal atoms. The negative ions of nonmetals are about twice the size of the corresponding nonmetal atoms.

1. Which is larger in each of the following? A. K or K + B. Al or Al 3+ C. S 2- or S 2. Which is smaller in each of the following? A. N 3- or N B. Cl or Cl - C. Sr 2+ or Sr

Ionic compounds Consist of positive and negative ions Have attractions called ionic bonds between positively and negatively charged ions Have high melting and boiling points Are solid at room Ionic Compounds

Salt is An Ionic Compound Sodium chloride in “table salt” is an example of an ionic compound. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

An ionic formula Consists of positively and negatively charged ions Is neutral Has charge balance total positive charge = total negative charge Uses subscript to indicate the number of ions needed to give charge balance Ionic Formulas

Ionic Formula of NaCl In an ionic formula, The symbol of the metal is written first followed by the symbol of the nonmetal The charges of the ions in the compound are not shown Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Charge Balance In MgCl 2 In MgCl 2 An Mg atom loses two valence electrons Two Cl atoms each gain one electron Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Writing Ionic Formulas from Charges Charge balance is used to write the formula for sodium nitride, a compound containing Na + and N 3−. Na + 3Na + N 3− = Na 3 N Na + 3(+1) + 1(3-) = 0

Write the correct formula for the ionic compound of A. Na + and S 2- 1) NaS 2) Na 2 S3) NaS 2 B. Al 3+ and Cl - 1) AlCl 3 2) AlCl 3) Al 3 Cl C. Mg 2+ and N 3- 1) MgN 2) Mg 2 N 3 3) Mg 3 N 2 Learning Check

Naming of Ionic Compounds In the name of an ionic compound, The positive ion (first ion) is named as the element The negative ion (second ion) is named by changing the end of the element name to –ide

Names of Some Common Ions

Learning Check Write the formulas and names for compounds of the following ions: Br − S 2− N 3− Na + Al 3+

Metals that Form More than One Cation Most transition elements have two or more positive ions (cations). Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Naming Variable Charge Metals Transition metals With two different ions use a Roman numeral after the name of the metal to indicate ionic charge. Zinc, silver, and cadmium form only one ion (Zn 2+, Ag +, and Cd 2+ )

Learning Check Select the correct name for each: A. Fe 2 S 3 1) iron sulfide 2) iron(II) sulfide 3) iron (III) sulfide B. CuO 1) copper oxide 2) copper(I) oxide 3) copper (II) oxide

Learning Check The correct formula for each of the following is: A. Copper (I) nitride 1) CuN2) CuN 3 3) Cu 3 N B. Lead (IV) oxide 1) PbO 2 2) PbO 3) Pb 2 O 4

Some Compounds with Polyatomic Ions Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

Select the correct formula for each of the following: A. aluminum nitrate 1) AlNO 3 2) Al(NO) 3 3) Al(NO 3 ) 3 B. copper(II) nitrate 1) CuNO 3 2) Cu(NO 3 ) 2 3) Cu 2 (NO 3 ) C. iron (III) hydroxide 1) FeOH2) Fe 3 OH3) Fe(OH) 3 D. tin(IV) hydroxide 1) Sn(OH) 4 2) Sn(OH) 2 3) Sn 4 (OH) Name each of the following compounds: A.Mg(NO 3 ) 2 B.Cu(ClO 3 ) 2 C.PbO 2 D.Fe 2 (SO 4 ) 3 E.Ba 3 (PO 3 ) 2