Compounds and Their Bonds

Valence Electrons

Octet Rule and Ions

Chemical Bonds

• What is a Chemical Bond?

• How do the 2 atoms stay together?

Chemical Bonds

• The electrons experience attraction

from both nuclei

• One pair of electrons = One bond

Valence Electrons

Electrons in the highest (outer) electron level

Octet Rule

Octet Rule

An octet in the outer shell makes atoms stable

Electrons are lost, gained or shared to form an

octet

Unpaired valence electrons strongly influence

bonding

Ionic Compounds

• What do you notice

about these Ionic

Compounds?

Ionic Compounds

Ionic compounds result when metals react with

nonmetals

Metals lose electrons to have a complete outer shell

Positive ions form when the number of electrons are

less than the number of protons

Group 1A metals ion 1+

Group 2A metals ion 2+

Group 3A metals ion 3+

1A 2A 3A

Formation of Sodium Ion

Sodium atom Sodium ion

Na e- – e Na +

2+8+1 - 1 = 2+8 [electrons]

11 p+ 11 p+

11 e- 10 e-

0 1+

Formation of Magnesium Ion

Magnesium atom Magnesium ion

e-

Mg e- – 2e Mg2+

2 + 8 + 2 - 2 = 2 + 8 [electrons]

12 p+ 12 p+

12 e- 10 e-

0 2+

Some Typical Ions with Positive

Charges (Cations)

Learning Check

A. How does Ca form a Ca2+ ion?

B. How does O form O2- ion?

Solution

A. How does Ca form a Ca2+ ion?

Loses 2 electrons to give full outer shell

2-8-8-2 2-8-8 (like Ar)

Solution

A. How does Ca form a Ca2+ ion?

Loses 2 electrons to give full outer shell

2-8-8-2 2-8-8 (like Ar)

B. How does O form O2- ion?

Solution

A. How does Ca form a Ca2+ ion?

Loses 2 electrons to give full outer shell

2-8-8-2 2-8-8 (like Ar)

B. How does O form O2- ion?

Gains 2 electrons to give full

outer shell

2-6 + 2e- 2-8 (like Ne)

Ions from Nonmetal Ions

• Which group(s) in the periodic table form

nonmetal ions?

• What must these nonmetals do to form an ion?

• What are the typical charges for these ions?

Fluoride Ion

unpaired electron octet

1 -

F + e F

2 + 7 +1 2 + 8

9 p+ 9 p+

9 e- 10 e-

0 1 -

ionic charge

e-

e-e-e-

e- e-

e-

e- e-

e- e-

e-e-

e-e-

Fluoride Ion

unpaired electron octet

1 -F + e F

e-

e-e-e-

e- e-

e-

e- e-

e- e-

e-e-

e-e-

Sulfur Ion

• What needs to happen in order for a sulfur

atom to become a sulfur ion?

Some Typical Ions with

Negative Charges (Anions)

Compounds and Their Bonds

Ionic Compounds

Naming Ionic Formulas

Ionic Compounds

Attraction between + ions and - ions

Electrons go from metals to nonmetals

electron transfer

metal nonmetal

ion+ ion–

Electrons lost = Electrons gained

Ionic Bonding

Ionic Bonding

Formulas of Ionic Compounds

Charge balance:

1+

1-

= 0

“Combining Capacities”

Writing a Formula

Write the formula for the ionic compound that

will form between Ba2+ and N3-.

Solution:

Ba3N2

Naming Binary Ionic Compounds

Contain 2 different elements

Name the metal first, then the nonmetal as -

ide.

Use name of a metal with a fixed charge

Groups 1A, 2A, 3A

and Ag, Zn, and Cd

Examples:

NaCl sodium chloride

ZnI2 zinc iodide

Al2O3 aluminum oxide

Learning Check

Complete the names of the following binary compounds:

Na3N sodium ______________

KBr potassium ______________

Al2O3 aluminum ______________

MgS magnesium ______________

Answers

Complete the names of the following binary compounds:

Na3N sodium nitride

KBr potassium ______________

Al2O3 aluminum ______________

MgS magnesium ______________

Answers

Complete the names of the following binary compounds:

Na3N sodium nitride

KBr potassium bromide

Al2O3 aluminum ______________

MgS magnesium ______________

Answers

Complete the names of the following binary compounds:

Na3N sodium nitride

KBr potassium bromide

Al2O3 aluminum oxide

MgS magnesium ______________

Answers

Complete the names of the following binary compounds:

Na3N sodium nitride

KBr potassium bromide

Al2O3 aluminum oxide

MgS magnesium sulfide