COVALENT BONDS 1 COVALENT BONDS Revised2.notebook February 21, - - PowerPoint PPT Presentation

COVALENT BONDS

Learning Targets 1 and 2 Pre Assess Big Ideas Post Assess I can define, identify, and diagram covalent bonds I can determine the number of bonds formed by atoms when forming molecules.

WHAT IS A COVALENT BOND? A covalent bond is when atoms share electrons.

H H

O

O

N N

What type of elements form covalent bonds?

• Covalent bonds often occur

between nonmetals. The reason that atoms are able to bond is that the attractions are strong enough in both directions (protons for electrons) from both atoms. There must also be room for electrons in the outer energy level of both atoms.

• In a covalent bond, both atoms

attract the two shared electrons a

t

the same time.

What groups will form covalent bonds?

HOW DO COVALENT BONDS FORM? Let's take a closer look on how covalent bonds form by viewing this tutorial...

TEACHERS DOMAIN COVALENT BONDING TUTORIAL

Learning Target Pre Assess Big Ideas Post Assess I can predict the formula for simple covalent molecules.

I can correctly name

covalent compounds. Learning Targets 3 and 4

Bell work (Write the questions).

• 1. What is a covalent bond?
• 2. What elements are involved in forming covalent bonds?
• 3. When two nonmetal atoms are close together, how does the

movement of electrons change?

• 4. What does the graph tell us about the potential energy of

hydrogen atoms when they form a covalent bond?

Lewis Dot

Lewis Dot Diagrams help to determine how many pairs of electrons can be shared. For example, how many pairs of electrons can be shared in Fluorine gas? Nitrogen gas?

F

• ne unpaired electron = single bond

N

three unpaired electron = triple bond

H H

Single Bonds

IN A SINGLE BOND, ATOMS SHARE A PAIR OF ELECTRONS.

H2 = Hydrogen Gas

Forms a single bond

H H

SHARES 2 ELECTRONS SHARES 2 ELECTRONS

Practice

Illustrate the covalent bonds between the following atoms:

Two Chlorine Atoms One Hydrogen and One Chlorine

• STRUCTURAL FORMULA
• LEWIS DOT STRUCTURE SHOWING THE SHARING OF

ELECTRONS

• FORMULA
• NAME OF THE COMPOUND

INCLUDE:

H Cl H Cl Cl Cl Cl Cl

ANSWERS

WERE YOU RIGHT?

Cl 2 Cl

Cl

Cl Cl

CHLORINE GAS

H

Cl

H Cl

HCl

Hydrogen Chloride

O O

DOUBLE BONDS

In a double bond, atoms share 2 pairs of electrons.

O O

• 2= Oxygen Gas

O O O O

PRACTICE

ILLUSTRATE THE COVALENT BONDS BETWEEN THE FOLLOWING: INCLUDE:

• STRUCTURAL FORMULA
• LEWIS DOT STRUCTURE SHOWING THE SHARING OF

ELECTRONS

• FORMULA
• NAME OF THE COMPOUND

ANSWERS

CO 2

C O

O

C O

O

CARBON DIOXIDE

WATER

O

H

H

H 2O

O

H H

WERE YOU RIGHT??

COVALENT BONDS

N2 = Nitrogen Gas

N N

Forms a triple bond

N N N N

TRIPLE BONDS

In a triple bond, atoms will share 3 pairs of electrons

N N

N2 = Nitrogen Gas

SHARES 6 ELECTRONS

S H A R E S 6 E L E C T R O N S

THE ATOMS IN A COVALENT BOND ARE MORE STABLE WHEN THEY ARE BONDED TOGETHER THAN WHEN THEY ARE APART

When are atoms the most stable?

THE LOWER THE ENERGY = THE MORE STABLE THE BOND

Learning Target Pre Assess Big Ideas Post Assess I can predict the formula for simple covalent molecules.

I can correctly name

covalent compounds. Learning Targets 3 and 4

Bell Work Take 2 minutes to think about ionic bonds and covalent bonds and how they form. Write down all of the similarities and differences that you can between the two in your composition books.

Now, "Give one and Get one" with 3 people at a different table and return to your seat.

Learning Target Pre Assess Big Ideas Post Assess I can distinguish between ionic and covalent compounds.

Learning Target 5

NAMING COMPOUNDS

COVALENT COMPOUNDS ARE NAMED USING PREFIXES TO INDICATE THE NUMBER OF EACH TYPE OF ATOM PRESENT IN THE MOLECULE

Mono = 1 Di = 2 Tri = 3 Tetra = 4 Penta =5 Hexa = 6

CO 2 = Carbon Dioxide Cl 2O = Dichlorine Monoxide

SO 3 = Sulfur Trioxide

Rules for Naming Binary Covalent Compounds

Rule 1. The element with the lower group number is written first in the name; the element with the higher group number is written second in the name. Exception: when the compound contains oxygen and a halogen, the name of the halogen is the first word in the name.

Rules for Naming Binary Covalent Compounds

Rule 2. If both elements are in the same group, the element with the higher period number is written

first in the name. Rule 3. The second element in the name is named as if it were an anion, i.e., by adding the suffix ­ ide to the name of the element.

Naming Binary Covalent Compounds

Rule 4. Greek prefixes (see the Table provided at the bottom of this page) are used to indicate the number of atoms of each nonmetal element in the chemical formula for the compound.

Exception: if the compound contains one atom of the element that is written first in the name, the prefix "mono­" is not used.

• cta­

CAN YOU NAME THE FOLLOWING?

• CO 2
• S 2O 3
• NO 2
• CCl 4
• SO
• N 2O 3