8th Chemistry - Ionic and Covalent Bonding

St. George's College

Subject: 8th CHEMISTRY

Teacher's notes

Objectives

Class: Ionic and Covalent

Vocabulary

Bonding Link and Learn

Date: August 31st In‐Class Survey

2009

Prepared by

1

8th Milton A ‐ Ionic Bonding Name

Oral Intervention

Sergio María Fernanda Alejandra Almendra Anna Paula Sandra E‐C Maia María Belén Alfredo Kinley Arianne Sandra M. Fiorella Rodrigo Giulia Jaime Stefano Bruno

2

8th Milton Alpha ‐ Ionic Bonding Name

Oral Intervention

Marcelo Antonella Paulo Alejandro Brenda Diego Gabriel Valeria Cristina Giuliana Joshua María Gracia Gonzalo N. Paolo Gonzalo R. Giorgio Nicolás María Claudia

3

Let's remember previous learned concepts...

4

Electron Number • The number of electrons in an atom can be determined by the atomic number (number of protons). As long as the atom is neutral, with no charge, the atomic number will be the number of electrons.

• The electrons in an atom are organized in energy levels.

5

Combining Atoms • All substances are made of atoms of one or more of the 100+ elements.

• Chemical bonding is the joining of atoms to form new substances.

• The properties of these new substances are different from the properties of the original elements.

• An interaction that holds two atoms together is called a chemical bond.

• When chemical bonds form, electrons are shared, gained or lost.

6

Bonding • Not all atoms bond in the same manner. In fact, some rarely bond at all.

• The number of electrons in the outermost energy level of an atom determines whether an atom will form bonds.

• Having 8 valence electrons is a special condition, these atoms do not usually form bonds, because they are stable atoms.

7

New knowledge beginning......

8

IONIC BONDING

9

Ionic Bonding • All atoms interact with other atoms to obtain stability, or filling up their last energy level with its maximum number of electrons.

• Ionic Bonds form between Metals and Non‐ Metals.

• Metals tend to lose electrons, becoming positive ions.

• Non‐Metals tend to gain electrons, becoming negative ions.

10

New things learned: The Electrostatic attraction of opposite charges sticks the ions together, that is called Ionic Bond.

Millions of ions bond together to form crystal as the attraction acts in all directions.

11

12

EXAMPLES

Metal

Non窶信etal

13

Properties of Ionic Compounds Ionic Compounds are made of Crystals (Crystalline Network), which can be split along certain angles.

Ionic compounds form huge crystals with a pattern that can be seen by X‐rays.

14

Properties of Ionic Compounds

ENERGY

Ionic Compounds have High Melting Points.

Opposite charges attract, forming strong ionic bonds, these forces of attraction act in all directions, trying to separate all the ions from a crylstal network takes a lot of energy.

15

Properties of Ionic Compounds Ionic Compounds are often Soluble in Water.

The Water colecule is neutral, however it has polar tendencies (positive from H, and negative from O). As a consequence, the slightly positive side of water interacts with the negative ions of ionic compounds, and the slightly negative side of water interacts with the positive ions of ionic compounds

16

17

Properties of Ionic Compounds Ionic Compounds Conduct Electricity when dissolved in water, but not in solid state.

Solid Ionic compounds, such as sodium chloride do not conduct electrivity in solid states, the ions are in a fixed position in the crystalline network (lattice).

These ions can't move to the charged poles or electrodes.

However, when dissolved in water, ions are free to move around.

18

19

COVALENT BONDING http://staff.aub.edu.lb/~hyaghi/LessonSamples/Atom/pages/explanations/cmpds.htm

20

Covalent Bonding • Covalent Bonds are formed between Non‐Metals.

• Metals tend to lose electrons, becoming positive ions.

• Non‐Metals tend to gain electrons, becoming negative ions.

• Two Non‐Metal atoms can gain electrons by sharing.

Shared electrons form COVALENT BONDS between Non‐Metal atoms.

21

Covalent bonding occurs in nonmetal compounds.

Use the highlighter to select the compounds that are covalently bonded.

H2O

HCl

NaF

CO2

LiO MgO

CH4

NH3

NaCl

Drag this to the target to reveal the answers.

22

A covalent bond is the chemical bond formed between two atoms when they share electrons in pairs. When atoms come near each other, their electrons are attracted towards the nucleus of the other atom. If the outside shell is not filled, this attraction becomes stonger.

The electrons are now being shared by both atoms, and they both have a full outer shell.

23

When atoms share electrons, we call it a covalent bond.

Cl

H Covalent bond

On the following pages, drag the atoms together to create compounds. You may need to rotate the atoms and get more than one copy to create your compounds

24

Answer

F

CL

25

Answer

H

O

26

H C

O

N

27

DOUBLE BONDS • Covalent bonds are formed when one pair of electrons (single bond), two pairs of electrons (double bond), and three pairs of electrons (triple bond) are shared; in the case of Carbon atoms, for example.

H x x

C

x

x x

+

x x

H

Single Bond

x

Hx C

x

x

H

x

H

4 Hydrogen

Carbon

Methane x x x

C x x

Carbon

x

+

O

Double Bond

x

O

x x

C x

x x

O

2 Oxygen 28

Properties of Covalent Compounds • Covalent compounds have: Low Melting Points Low Boiling Points • Covalent compounds DO NOT have charged particles, as a consequence: Are NOT Conductors of Electricity.

They do not dissolve in water.

Tend to dissolve in non‐polar solvents (bencene).

29

Structures of Carbon • Carbon is present in nature in 4 forms: Amorphous carbon, Graphite, Diamond, and C60. http://tinyurl.com/ms23jy

• Diamonds are the hardest substances on Earth.

• Diamond is made only from carbon atoms.

• Each carbon atom forms 4 strong covalent bonds with its neighbors, they form a giant covalent structure. http://tinyurl.com/ku5wh3

• Diamonds and Graphite are allotropes of Carbon, or elements with different forms in the same state.

• The carbon atoms in graphite are also http://tinyurl.com/m6q7qk held together in a giant covalent structure, however its properties are different, because they form layers.

http://tinyurl.com/l8oblm

30

http://www.youtube.com/watch?v=QqjcCvzWwww&NR=1

31

32

Resources Used Slide (Group)

Description

Resource

Origin

G1 ‐ 2

Image

Milton

http://bit.ly/XQqEw

G1 ‐ 3

Image

Milton

http://bit.ly/XQqEw

G1 ‐ 4 Animation Idea Chemical Bonding 1 Chemical Bonding 2

Notebook Gallery http://tinyurl.com/mkqeo9 http://tinyurl.com/mc33kn

G1 ‐ 6

Images

G1 ‐ 8

Animation Check this out

Notebook Gallery

G1 ‐ 9

Animation Ionic Bonding

http://tinyurl.com/l4psxt

G1 ‐ 10 Animation Electron transfer

Unknown

G1 ‐ 11 Animation Ionic Bonding

Unknown

G1 ‐ 12 Animation Interactive Periodic Table

Notebook Gallery

G1 ‐ 14 Images

Crystal Network 1 Crystal Network 2 Sodium Chloride

http://tinyurl.com/kndqwp http://tinyurl.com/kndqwp http://tinyurl.com/ntw698

G1 ‐ 15 Image

Crystalline Network

http://tinyurl.com/m2xg7s

G1 ‐ 16 Image

Salt solubility

Unknown

G1 ‐ 17 Animation Salt sollubility in water G1 ‐ 18 Image

Unknown

Conductivity of Ionic Compounds http://tinyurl.com/lz93bd

G1 ‐ 19 Animation Ionic vs Covalent Bonding

http://tinyurl.com/lcghho

G1 ‐ 20 Animation Covalent Bonding

http://tinyurl.com/l4psxt

22 ‐ 27 Slides

Covalent Bonding

http://tinyurl.com/mztpsh

G1 ‐ 30 Images

Diamond Diamond Structure Graphite Graphite Structure

http://tinyurl.com/ms23jy

G1 ‐ 31 Video

Ionic vs Covalent Compounds

http://tinyurl.com/c99ubw

G1 ‐ 32 Animation Chemical Compounds Structure

Unknown

33

Teacher's Notes This class has been designed to cover the topics of Ionic Bonding from Monday August 31st till Friday September 4th.

For further knowledge about this topic: 1. Conduct a thorough search under the topic: Ionic Bonding on the Web, books and magazines.

2. If findings are not specific, ask your teacher for suggestions.

BACK 34

Objectives • Identify and describe the properties and characteristics of Ionic.

• Review and recognize compounds with different types of bonding, and compare their physical properties.

Note: All, or most, of the objectives will be covered during class time, however the student must be responsible for those objectives not covered or concluded.

BACK 35

Vocabulary • • • • •

Electron: Energy Level: Octet Rule: Ionic bonding: Crystalline Network:

Note: Most of the vocabulary words will be covered during class time, however the student must be responsible for those words not covered or concluded.

BACK 36

Link and Learn You can visit the following websites to improve your understanding on the present topic: • • • • •

http://www.chemguide.co.uk/atoms/bonding/ionic.html http://tinyurl.com/8yb6b http://science‐learning2009.wikispaces.com http://learningandscience.blogspot.com http://libraryatstgeorge.blogspot.com

BACK 37

Prepared by

Gerardo LAZARO Science Lead Teacher Email: glazaro@sanjorge.edu.pe Wiki: http://science‐learning2009.wikispaces.com Blog: http://learningandscience.blogspot.com Twitter: http://twitter.com/glazaro

BACK 38

SURVEY If you want to contribute in improving your Chemistry class, click in the survey link:

Term III ‐ 8th A ‐ Class 4 Term III ‐ 8th Alpha ‐ Class 4

39

Term III ­ Class 4 Ionic and Covalent Bonding

Grade: Subject: Date:

8th Grade Chemistry ­ A August 31st, 2009

40

1

What was your UNDERSTANDING of the topic: "Ionic and Covalent Bonding"

A

I understood 25% of the whole topic

B

I understood 50% of the whole topic

C

I understood 75% of the whole topic

D

I understood 100% of the whole topic

E

I didn't understand the class

41

2

What was your level of EFFORT to understand the topic?

A

My effort level was 25%

B

My effort level was 50%

C

My effort level was 75%

D

My effort level was 100%

E

I didn't put any effort

42

3

What RESOURCES helped you understand the topic?

A

Text

B

Images

C

Animations

D

Videos

E

Teacher's Speech

F

None

G

Other

43

4

How does the SMART Board help you understand the topic?

A

It helps me visualize concepts

B

It helps understand difficult concepts

C

Touching things helps me learn

D

Interacting with the information makes it easier to understand

E

I prefer less effects or audiovisual resources

F

It doesn't really help much

G

I don't like it

44

Term III ­ Class 4 Ionic and Covalent Bonding

Grade: Subject: Date:

8th Grade Chemistry ­ Alpha August 31st, 2009

45

1

What was your UNDERSTANDING of the topic: "Ionic and Covalent Bonding"?

A

I understood 25% of the whole topic

B

I understood 50% of the whole topic

C

I understood 75% of the whole topic

D

I understood 100% of the whole topic

E

I didn't understand the class

46

2

What was your level of EFFORT to understand the topic?

A

My effort level was 25%

B

My effort level was 50%

C

My effort level was 75%

D

My effort level was 100%

E

I didn't put any effort

47

3

What RESOURCES helped you understand the topic?

A

Text

B

Images

C

Animations

D

Videos

E

Teacher's Speech

F

None

G

Other

48

4

How does the SMART Board help you understand the topic?

A

It helps me visualize concepts

B

It helps understand difficult concepts

C

Touching things helps me learn

D

Interacting with the information makes it easier to understand

E

I prefer less effects or audiovisual resources

F

It doesn't really help much

G

I don't like it

49