Properties of Ionic Compounds Forming NaCl from Na and Cl 2 A metal atom can transfer an electron to a nonmetal. A metal atom can transfer an electron to a nonmetal. The resulting cation and anion are attracted to each other by electrostatic forces. The resulting cation and anion are attracted to each other by electrostatic forces.

The Octet Rule – Ionic Compounds Ionic compounds tend to form so that each atom, by gaining or losing electrons, has an electron arrangement like that of a noble gas.

CATION + ANION ---> COMPOUND COMPOUND CATION + ANION ---> COMPOUND COMPOUND A neutral compound requires equal number of + equal number of + and - charges. A neutral compound requires equal number of + equal number of + and - charges. COMPOUNDS FORMED FROM IONS Na + + Cl - --> NaCl

Electron Dot Notation

Predicting Ionic Charges Group 1: Lose 1 electron to form 1+ ions H+H+H+H+ Li + Na + K+K+K+K+

Predicting Ionic Charges Group 2: Loses 2 electrons to form 2+ ions Be 2+ Mg 2+ Ca 2+ Sr 2+ Ba 2+

Predicting Ionic Charges Group 13: Loses 3 Loses 3 electrons to form 3+ ions B 3+ Al 3+ Ga 3+

Predicting Ionic Charges Group 14: Loses 4 Loses 4 electrons or gains 4 electrons Caution! C 2 2- and C 4- are both called carbide

Predicting Ionic Charges Group 15: Gains 3 Gains 3 electrons to form 3- ions N 3- P 3- As 3- Nitride Phosphide Arsenide

Predicting Ionic Charges Group 16: Gains 2 Gains 2 electrons to form 2- ions O 2- S 2- Se 2- Oxide Sulfide Selenide

Predicting Ionic Charges Group 17: Gains 1 Gains 1 electron to form 1- ions F 1- Cl 1- Br 1- Fluoride Chloride Bromide I 1- Iodide

Predicting Ionic Charges Group 18: Stable Noble gases do not form ions! Stable Noble gases do not form ions!

Predicting Ionic Charges Groups : Many transition elements Many transition elements have more than one possible oxidation state. have more than one possible oxidation state. Iron(II) = Fe 2+ Iron(III) = Fe 3+

Predicting Ionic Charges Groups : Some transition elements Some transition elements have only one possible oxidation state. have only one possible oxidation state. Zinc = Zn 2+ Silver = Ag +

Predicting Charges on Monatomic Ions KNOW THESE !!!! Be 2+

Writing Ionic Compound Formulas Example: Iron(III) chloride 1. Write the formulas for the cation and anion, including CHARGES! Fe 3+ Cl - 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Not balanced! 3

Writing Ionic Compound Formulas Example: Aluminum sulfide 1. Write the formulas for the cation and anion, including CHARGES! Al 3+ S Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Not balanced! 23

Formulas of Ionic Compounds Formulas of ionic compounds are determined from the charges on the ions atoms ions     – Na  +  F :  Na + : F :  NaF     sodium + fluorine sodium fluoride formula Charge balance: = 0

Some Ionic Compounds Mg 2+ + N > Mg 3 N 2 magnesium nitride Sn 4+ + O > SnO 2 Tin (IV) oxide calcium fluoride Ca F -  CaF 2

Monatomic Ions

Learning Check Write the correct formula for the compounds containing the following ions: 1. Na +, S 2- a) NaS b) Na 2 Sc) NaS 2 2. Al 3+, Cl - a) AlCl 3 b) AlCl c) Al 3 Cl 3. Mg 2+, N 3- a) MgN b) Mg 2 N 3 c) Mg 3 N 2

Solution 1. Na +, S 2- b) Na 2 S 2. Al 3+, Cl - a) AlCl 3 3. Mg 2+, N 3- c) Mg 3 N 2