Ionic Compounds

Lewis Dot DiagramsChemical Interactions Occur between

the Valence Electrons

Dots: represent valence electrons

When atoms combine to make molecules, they form chemical bonds.

Valence electron

interaction

Forming Chemical Bonds

• Octet Rule Atoms will form bonds by: – Sharing– Giving or – Taking

electrons to

complete

their octet

Higher energy farther away from nucleus

Atoms form ions to have stable electron configurations (similar

to noble gases)

hh

Ionic Bonds

• Ionic Bonds form when one atom (nonmetal) gains electrons and the other atom (metal) loses electrons in order to gain stability.

• Ionic Bonds form between a metal (cation) and a nonmetal (anion).

To form an ion, lithium will most likely:

1 2 3 4

5% 5%

91%

0%

1. Gain 1 electron

2. Gain 2 electrons

3. Lose 1 electron

4. Lose 2 electrons

Forming Chemical Bonds• Lithium

–Better to lose 1 electron or to gain 7

electrons?

X

Therefore, as an ion lithium will have what charge?

1 2 3 4

73%

0%

27%

0%

1. 1+

2. 2+

3. 1-

4. 2-

Ionic Bonds • Atoms gain or lose its electrons

+

NaCl - salt

Chemical Interactions Occur between the Valence Electrons

Lewis structures are simpler to do & see

Formation of MgCl2

Formation of Na2S

• Write down the chemical formula for Aluminum Flouride

Formation of AlF3

Today is a practice Day!

• We need to be able to name ions given chemical formula

• We need to be able to determine the chemical formula given the name

Valence Electrons Noble Gas Structure = Octet

1,2 3,4,5,6,7,8

IONIC BONDS / Cations and Anions

Cation – positive ions

Transition Metals use

Roman Numerals to tell you the ox #

Anion – negative ions

Oxidation Numbers

• Oxidation Numbers

- indicated # of e’ lost, gained or shared.

Ex. Oxidation number of chlorine is -1

Halogens will have an oxidation number of:

1 2 -1 -2

0% 0%0%0%

1. +1

2. +2

3. -1

4. -2

Alkaline earth metals will have an oxidation number of:

1 2 -1 -2

0% 0%0%0%

1. +1

2. +2

3. -1

4. -2

We will name binary compounds together

• Using pages 156- 158• Describe how to name cations

and anions when they are by themselves

Naming Binary Ionic Compounds

• Write the name of the ionic compound, Ca2N3.

• Write the name of the ionic compound, K2O.

What is the name of BeBr2?

Boron bro

mine

Beryllium bro

m...

Bromide beryll..

.

Beryllium bro

m...

Beryllide bro

m...

0% 0% 0%0%0%

1. Boron bromine

2. Beryllium bromine

3. Bromide beryllide

4. Beryllium bromide

5. Beryllide bromide

Metals with Variable Charges

• Many transition metals can form more than one type of cation.

• For this reason, you must show the oxidation number in the name using Roman Numerals

Naming Binary Ionic Compounds with Transition

Metal Cations• Write the name of

the ionic compound, Cu2O..

• Write the name of the ionic compound, NiS.

What is the name for SnBr2?

Bromide Tin

Tin Bromide

Tin (I) Bro

mid...

Tin (II) B

romi...

Tin (III) B

rom...

Tin (IV) B

romi...

0% 0% 0%0%0%0%

1. Bromide Tin

2. Tin Bromide

3. Tin (I) Bromide

4. Tin (II) Bromide

5. Tin (III) Bromide

6. Tin (IV) Bromide

What is the name for FeI3?

Iron io

dide

Iron (I)

iodid...

Iron (II

) iodi...

Iron (II

I) iod...

0% 0%0%0%

1. Iron iodide

2. Iron (I) iodide

3. Iron (II) iodide

4. Iron (III) iodide

What is the name for MnS?

Manganese

sulf..

.

Manganese

(I) ...

Manganese

(II)...

Manganese

(III...

0% 0%0%0%

1. Manganese sulfide

2. Manganese (I) sulfide

3. Manganese (II) sulfide

4. Manganese (III) sulfide

Exceptions:• Some of the transition metals

have only one ionic charge:

–Do not need to use roman numerals for these:

–Silver is always 1+ (Ag1+)–Cadmium and Zinc are always

2+ (Cd2+ and Zn2+)

Writing Formulas for Binary Ionic Compounds

• Write the formula for barium iodide.

• Write the formula for sodium oxide.

• Write the formula for aluminum nitride.

• Write the formula for copper (I) sulfide.

Criss-Cross Method for Writing Formulas

- You can write the oxidationnumber and criss-cross them as subscripts.

- Note – if not in lowest termsyou must reduce the subscripts(ex. Magnesium oxide)

Al3+ S2-2 3

= Al2S3

What is the formula for aluminum bromide?

AlBr AlBr2

Al3Br Br3Al

AlBr3

0% 0% 0%0%0%

1. AlBr

2. AlBr2

3. Al3Br

4. Br3Al

5. AlBr3

What is the formula for magnesium oxide?

MgO

Mg2

O2

MgO

2

Mg2

O O

Mg

0% 0% 0%0%0%

1. MgO

2. Mg2O2

3. MgO2

4. Mg2O

5. OMg

Write the formula for titanium (II) chloride.

TiCl Ti2Cl

TiCl2

Ti2Cl2

0% 0%0%0%

1. TiCl

2. Ti2Cl

3. TiCl24. Ti2Cl2

Write the formula for tin (IV) oxide.

SnO

SnO4

SnO2

Sn4O

Sn2O

0% 0% 0%0%0%

1. SnO

2. SnO4

3. SnO2

4. Sn4O

5. Sn2O

POLYATOMIC IONS• Not all compounds are made of only 2

types of atoms• poly – “many”

Memorize the polyatomic ions from p. 170.

Tricks for Polyatomic Naming

Perchlorate per+root+ate ClO4-1

chlorate root+ate ClO3-1

chlorite root+ite ClO2-1

Hypochlorite hypo+root+ite ClO-1

Prefixes and suffixes designate number of oxygens

Naming Polyatomic Ionic Compounds

• Polyatomic ionic compounds are named just like binary ionic compounds.

• Exception: be sure to enclose the polyatomic ion in parentheses before writing the subscript (only necessary if subscript is not 1).

• Ex. Barium hydroxide = Ba(OH)2

Write the formula for Calcium Nitrate.

CaNO2

Ca(NO2)2

Ca2NO3

Ca2NO2

Ca(NO3)2

0% 0% 0%0%0%

1. CaNO2

2. Ca(NO2)2

3. Ca2NO3

4. Ca2NO2

5. Ca(NO3)2

Write the formula for Magnesium Phosphate.

MgP

O4

Mg3

(PO4)2

Mg4

(PO3)2

MgP

O3

Mg(P

O4)2

0% 0% 0%0%0%

1. MgPO4

2. Mg3(PO4)2

3. Mg4(PO3)2

4. MgPO3

5. Mg(PO4)2

Naming Ionic Compounds