Ionic Bonding in Review

Ionic Bonds– Between metals & nonmetals– Electrons form a give take

relationship• metals give e- (cation) • nonmetal take e- (anion)

– Held together by attraction of opposite charges

Names to Formulas

You have to be able to determine the charges of ions …

Predicting Ionic Charges from periodic tableGroup 1: Lose 1 electron to form 1+ ions

H+ Li+ Na+ K+

Group 2: Loses 2 electrons to form 2+ ionsBe2+ Mg2+ Ca2+ Sr2+ Ba2+

Predicting Ionic Charges from periodic table

Group 13:Loses 3 electrons to form 3+ ionsB3+ Al3+ Ga3+

Predicting Ionic Charges from periodic table

Group 14:Lose 4 electrons or gain 4 electrons? 4+ or 4- ion

Predicting Ionic Charges from periodic table

Group 15: Gains 3 electrons to form 3- ions

N3-

P3-

As3-

Nitride

Phosphide

Arsenide

Predicting Ionic Charges from periodic table

Group 16: Gains 2 electrons to form 2- ions

O2-

S2-

Se2-

Oxide

Sulfide

Selenide

Predicting Ionic Charges from periodic table

Group 17: Gains 1 electron to form 1- ions

F1-

Cl1-

Br1-Fluoride

Chloride

Bromide

I1- Iodide

Predicting Ionic Charges from periodic table

Group 18:Stable Noble gases do not form ions!

Predicting Ionic Charges from periodic table

Groups 3 - 12: Many transition elements have more than one possible oxidation state.

The only way to know their charge is by looking at the roman numeral in the name !!!

Iron(II) = Fe2+

Iron(III) = Fe3+

Predicting Ionic Charges from periodic table

Groups 3 - 12:Some transition elements have only one possible oxidation state.

Write these on your Periodic TableZinc = Zn2+

Silver = Ag+

Predicting Ionic Charges from periodic table

2+

1+

Predicting Ionic Charges of Polyatomic IonsPolyatomic Ions– The prefix poly- means many in Greek. – ion consisting of a molecule with many covalently bonded atoms – act as a single unit– Usually end in –ate & –ite – To know their charge memorize the list or look it up– -ide usually indicates binary compounds except hydroxide

Rules for Formulas• Write the cation (metal) first. Write the

anion (nonmetal) second.• The net ionic charge is zero.• Use subscripts to indicate multiple ions.• Write the formula unit in the lowest whole

number ratio.• Use parenthesis to indicate multiple

polyatomic ions.

Class Practice Names to Formulas

Silver Chloride

AgCl

Ag+1 Cl-1

Lead (IV) Sulfide (Galena)

PbS2

Lead (IV) Pb+4

S-2

Zinc Phosphide

Zn3P2

Zn+2 P-3

Aluminum Oxide

Al2O3

Al+3 O-2

Magnesium Sulfate

MgSO4

Mg+2 SO4-2

Iron (II) oxide

FeO

Iron (II) Fe+2

O-2

Iron (III) oxide (Hematite)

Fe2O3

Iron (III) Fe+3

O-2

Copper (II) Nitrate

Cu(NO3)2

Copper (II)Cu+2

NO3-1

Mistakes to Avoid• Roman numerals are not

written in the formula

• Charges are not written in the formula

• Don’t drop polyatomic subscripts

• Hydroxide, OH, needs parentheses to indicate multiples.

• Cu(II)O CuO

• K+1Br-1 KBr

• CaNO2 Ca(NO3)2

• CaOH2 Ca(OH)2

Examples #1- Formulas to Names

CuSO3

copper

I’m a polyatomi

c ion

1. Write the names of the ions

Final Name

sulfite(II)

x

X + (- 2) = 0

X = +2

Cu SO3

= 0

You must know the charge on the sulfite ion is -2

The sum of the positive and negative charges must equal zero

2. Determine the charge of the positive ion

-

2

+2 +2

Next

+22. Does the cation form more than one oxidation charge?

Examples #2- Formulas to Names

KMnO4

potassium

I’m a polyatomi

c ion

1. Write the names of the ions

Final Name

permanganate

2. Does the cation form more than one oxidation charge?

Examples #3- Formulas to Names

NH4NO3

ammonium

I’m a polyatomi

c ion

1. Write the names of the ions

Final Name

nitrate

2. Does the cation form more than one oxidation charge?

Examples #4- Formulas to Names

SnF2

tin

2. Does the cation form more than one oxidation charge?

1. Write the names of the ions

Final Name

fluoride(II)

Snx (F-1)2 = 0

X + 2(-1) = 0X = +2

Examples #5- Formulas to Names

Ba(ClO4)2

barium

I’m a polyatomi

c ion

1. Write the names of the ions

Final Name

perchlorate

2. Does the cation form more than one oxidation charge?

Examples #6- Formulas to Names

Cu2S

copper

I’m not a polyatomi

c ion

1. Write the names of the ions

Final Name

sulfide(I)

2Cux (S)-2 = 0

2X + (-2) = 0X = +12. Does the cation form more

than one oxidation charge?