Net Ionic Equations (8-4)• Show only the species (atoms/ions) participating in a

reaction o Single displacement reaction – exchange electronso Double displacement reaction – form new bonds (ionic

or covalent)• Steps 1. From formula equation write complete ionic equation

• use ion symbols for aqueous species• use element, formula symbols for (g), (l), (s)

2. Cancel spectator ions (ions not forming new bonds)

Can be written for:o Single Displacement Reactions (electron transfer

reactions)• One spectator ion• Charges must balance

o Double Displacement Reactions (bond forming reactions)

• Two spectator ions• Charges on reactants side must sum up to zero

To predict the products of single-replacement reactions. Refer to the activity series (page 281 or appendix A, page 832)

• Is the free element above the element to be replaced in the compound?

• If yes, the reaction will occur

• Is the free element below the element to be replaced in the compound?

• If yes, then a reaction will NOT occur

The more active an element is, the more likely it will form compounds!

Simple Activity Series of Metals

KCaNaMgAlZnFeNiPbH2

CuAgAu

Increasing ReactivityDecreasing

Reactivity

Activity Series of Halogens

F2

Cl2Br2

I2

Increasing Reactivity

Decreasing Reactivity

Formula Equation:

Cu (s) + 2 AgNO3 (aq) Cu(NO3)2 (aq) + 2 Ag (s)

Complete Ionic Equation:

Cu (s) + 2 Ag1+ (aq) + 2 NO31- (aq) Cu2+ (aq) + 2 NO3

1- (aq) + 2 Ag (s)

Identify Spectator Ion:

NO31- is found on both sides of the yields sign and will cancel out.

Net Ionic Equation:

Cu (s) + 2 Ag1+ (aq) Cu2+ (aq) + 2 Ag (s)

Note that charges balance. There are 2(+) charges on the reactants side and 2(+) charges on the products side.

Example – Single DisplacementCheck Activity Series first!

A Precipitation Reaction must produce a new solid substance.

Use solubility rules (p. 284) to decide whether a precipitation will take place:

•Reactants are usually all soluble ionic compounds (will dissolve easily in water).

•If one of the ions from reactant #1 will form an insoluble compound with an ion from reactant #2, a precipitation reaction will take place. (Insoluble means will not dissolve in water.)

Some Simple Solubility Rules

• All compounds of Group 1 and NH4+ are soluble.

• All nitrates are soluble.• All halides, except those of Ag+ and Pb2+, are

soluble.• All sulfates, except Ca2+, Sr2+, Ba2+, Hg2

2+, and Pb2+ are soluble.

• All carbonates, except those of Group 1 and NH4+,

are insoluble.• Most hydroxides, except those of Group 1 and NH4

+, are insoluble.

Example – Double Replacement

Formula Equation:

AgNO3 (aq) + NaCl (aq) AgCl + NaNO3

Complete Ionic Equation:

Ag1+ (aq) + NO31- (aq) + Na1+ (aq) + Cl1- (aq) AgCl (s) + Na1+ (aq) + NO3

1- (aq)

Identify Spectator Ions:

Na1+ and NO31- are found on both sides of the yields sign and will cancel out.

Net Ionic Equation:

Ag1+ (aq) + Cl1- (aq) AgCl (s)

Note that charges balance. There is a net zero charge [(1+) + (1-)] on the reactants side and zero charge on the products side.

(s) (aq)