Theme: The Atom Topic: The Structure of the Atom

Theme: The Atom
Topic: The Structure of the Atom
Basic Education - Cycle 3
Grade - 9
Subject: Chemistry

Section - 1:
Learning Objectives:

• Describe the historical development of the atomic model )Greek, Dalton, Rutherford, Bohr(.
• Describe Rutherford's model of the atom and the evidence that support it.

Specific Objectives:
1. Compare the different models of the atom.
2. Explain how the atomic theory has changed as scientists have discovered new information about the atom.
Period -  Block 1(50 min):
Pages 17/ 18 Student Book
 Activity:
Make a model of an atom using different objects.
Preparation:

• Different objects: Bolts (B), nuts (N) tiny marbles (M),washers (W)
• Modeling clay and toothpicks
• Table for recording results of investigation (a table for each group)

Teaching Strategy

• Divide the students of the class into groups of four.
• Have students bury 3 -7 different objects in the modeling clay and make it in the form of a ball.
• he groups trade balls of clay with other group.

Ask the students:
- How many objects do you expect to find in the clay ball? Record your answer.

• Students use a broken - off toothpick as a probe to touch a hidden object. Repeat 20 times.
• Find out how many of each kind of object are in the ball, without pulling apart the clay ball.
• Students fill the following table with E, if probe hits nothing, and O, if probe hits an object. Also, write the letter of the corresponding object

Table for tecording Results

Probe hit object

Kind of object

Analysis:
Have students answer the following questions:
- How many objects did you find?
- Were you right? )Compare to table recording(
- What inference can you make about the quantity and identity of the hidden parts of the clay ball?

Conclusion:
Using indirect information we can infer the identity and the quantity of the hidden parts of a model.

Focus:
Discuss Democritus Proposition with Students.
Mention that color exists by convention, sweet and bitter by convention, but atoms and void exist in reality.
Mention to them that Democritus proposed that all matter is composed of tiny particles, called atomus, you know them as atoms.
Ask them to decide whether Democritus' theory about the atom “ matter is made up of tiny particles which are indivisible”, “ Matter is continuous” , is correct or even partly correct.
Then ask them which parts of his theory might have been changed in the 2500 years since it was first proposed.
Ask the students to give examples, from every day life, that show matter is discontinuous, using the teaching transparency T1

Teaching Transparency “Gold Atom” (T1)

Teaching Strategy
Reading Dalton's Atomic Theory (1800)
Have the students name some elements in the free form and in the combined form.

Activity:

1. Group the students in four.

- Have each group state the four postulates of Dalton's theory in their own words.

- Have the students critique each other for accuracy and clarity.

2. Refer to the diagram of different compounds )water, carbon dioxide and table salt( to show how elements combine in proportions and how the same elements always combine in the same proportions to make the same compounds.Use Teaching Transparency (T2)

• Question:

1. Give the names of the elements composing each substance and indicate how many atoms are there in each molecule. (Refer to Teaching Transparency T3)
2. “ An atom is the smallest particle into which an element can be divided and still be that element”. Is this definition still accurate? Give your opinion.

 

 

                                                                                                                                                                                                                                                 Teaching Transparency T3

Section – 1 (Continued)

Period 2 (50 min): Pages 19/ 20  Student Book

• Ask the students what is electric charge. Mention to them that there are two types of electric charge positive and negative. Objects with opposite charges attract each other, while objects with the same charge push each other away.
• Point out that:

• Have the students draw the “ Plum Pudding “ model.

 

Reading. Rutherford’s Atomic Model (1911)

Using the transparency illustrate the steps and results of Rutherford’s Gold Foil Experiment.

Teaching Transparency “Rutherford’s Gold Foil” Experiment (T4)

 

 

 

 

 

Teaching Transparency Compare Thomson’s Model and Rutherford’s Model (T5)

 

 

 

 

 

 

 

 

 

 

 

 

Focus on the Rutherford’ nuclear model of the atom.

 

• Ask the students:

• To come up with examples of things differing in size by a factor of 1000 000.
• In what part of an atom is most of its mass located?
• List two differences between atomic theory described by Thomson and that described by Rutherford.
• Draw Rutherford’s proposed planetary model of the atom. The model compares electrons to planets and the nucleus to the sun.

Bohr's Atomic Model

Teaching Transparency Bohr’s Atomic Model (1913) (T6)

 

 

 

• Point out Bohr suggested that electrons travel around the nucleus in definite paths.

• Stress that Bohr’s model was a valuable tool in predicting some atomic behavior but the atomic theory still had room for improvement.

• Point out that according to the current theory:

• Draw the attention of the students to the fact that, the more dots in the cloud the more likely an electron would be found there.

• Ask the students:

• Identify the difference in how Bohr’s theory and the modern theory describe the location of electrons.
• Draw a time line to show how the atomic theory has changed over the past several hundred years. (Draw the atomic model and associate to it the name of the scientist and the date.)
• Construct models of Thomson's plum pudding atom and Rutherford's nuclear atom Using simple materials: Cardboard, construction paper, colored pencils ,string,  cotton balls .

 

 

 

 

Theme: The Atom Topic: The Structure of the Atom

Theme: The Atom
Topic: The Structure of the Atom
Basic Education - Cycle 3
Grade - 9
Subject: Chemistry

Section - 1:
Learning Objectives:

• Describe the historical development of the atomic model )Greek, Dalton, Rutherford, Bohr(.
• Describe Rutherford's model of the atom and the evidence that support it.

Specific Objectives:
1. Compare the different models of the atom.
2. Explain how the atomic theory has changed as scientists have discovered new information about the atom.
Period -  Block 1(50 min):
Pages 17/ 18 Student Book
 Activity:
Make a model of an atom using different objects.
Preparation:

• Different objects: Bolts (B), nuts (N) tiny marbles (M),washers (W)
• Modeling clay and toothpicks
• Table for recording results of investigation (a table for each group)

Teaching Strategy

• Divide the students of the class into groups of four.
• Have students bury 3 -7 different objects in the modeling clay and make it in the form of a ball.
• he groups trade balls of clay with other group.

Ask the students:
- How many objects do you expect to find in the clay ball? Record your answer.

• Students use a broken - off toothpick as a probe to touch a hidden object. Repeat 20 times.
• Find out how many of each kind of object are in the ball, without pulling apart the clay ball.
• Students fill the following table with E, if probe hits nothing, and O, if probe hits an object. Also, write the letter of the corresponding object

Table for tecording Results

Probe hit object

Kind of object

Analysis:
Have students answer the following questions:
- How many objects did you find?
- Were you right? )Compare to table recording(
- What inference can you make about the quantity and identity of the hidden parts of the clay ball?

Conclusion:
Using indirect information we can infer the identity and the quantity of the hidden parts of a model.

Focus:
Discuss Democritus Proposition with Students.
Mention that color exists by convention, sweet and bitter by convention, but atoms and void exist in reality.
Mention to them that Democritus proposed that all matter is composed of tiny particles, called atomus, you know them as atoms.
Ask them to decide whether Democritus' theory about the atom “ matter is made up of tiny particles which are indivisible”, “ Matter is continuous” , is correct or even partly correct.
Then ask them which parts of his theory might have been changed in the 2500 years since it was first proposed.
Ask the students to give examples, from every day life, that show matter is discontinuous, using the teaching transparency T1

Teaching Transparency “Gold Atom” (T1)

Teaching Strategy
Reading Dalton's Atomic Theory (1800)
Have the students name some elements in the free form and in the combined form.

Activity:

1. Group the students in four.

- Have each group state the four postulates of Dalton's theory in their own words.

- Have the students critique each other for accuracy and clarity.

2. Refer to the diagram of different compounds )water, carbon dioxide and table salt( to show how elements combine in proportions and how the same elements always combine in the same proportions to make the same compounds.Use Teaching Transparency (T2)

• Question:

1. Give the names of the elements composing each substance and indicate how many atoms are there in each molecule. (Refer to Teaching Transparency T3)
2. “ An atom is the smallest particle into which an element can be divided and still be that element”. Is this definition still accurate? Give your opinion.

 

 

                                                                                                                                                                                                                                                 Teaching Transparency T3

Section – 1 (Continued)

Period 2 (50 min): Pages 19/ 20  Student Book

• Ask the students what is electric charge. Mention to them that there are two types of electric charge positive and negative. Objects with opposite charges attract each other, while objects with the same charge push each other away.
• Point out that:

• Have the students draw the “ Plum Pudding “ model.

 

Reading. Rutherford’s Atomic Model (1911)

Using the transparency illustrate the steps and results of Rutherford’s Gold Foil Experiment.

Teaching Transparency “Rutherford’s Gold Foil” Experiment (T4)

 

 

 

 

 

Teaching Transparency Compare Thomson’s Model and Rutherford’s Model (T5)

 

 

 

 

 

 

 

 

 

 

 

 

Focus on the Rutherford’ nuclear model of the atom.

 

• Ask the students:

• To come up with examples of things differing in size by a factor of 1000 000.
• In what part of an atom is most of its mass located?
• List two differences between atomic theory described by Thomson and that described by Rutherford.
• Draw Rutherford’s proposed planetary model of the atom. The model compares electrons to planets and the nucleus to the sun.

Bohr's Atomic Model

Teaching Transparency Bohr’s Atomic Model (1913) (T6)

 

 

 

• Point out Bohr suggested that electrons travel around the nucleus in definite paths.

• Stress that Bohr’s model was a valuable tool in predicting some atomic behavior but the atomic theory still had room for improvement.

• Point out that according to the current theory:

• Draw the attention of the students to the fact that, the more dots in the cloud the more likely an electron would be found there.

• Ask the students:

• Identify the difference in how Bohr’s theory and the modern theory describe the location of electrons.
• Draw a time line to show how the atomic theory has changed over the past several hundred years. (Draw the atomic model and associate to it the name of the scientist and the date.)
• Construct models of Thomson's plum pudding atom and Rutherford's nuclear atom Using simple materials: Cardboard, construction paper, colored pencils ,string,  cotton balls .

 

 

 

 

Theme: The Atom Topic: The Structure of the Atom

Theme: The Atom
Topic: The Structure of the Atom
Basic Education - Cycle 3
Grade - 9
Subject: Chemistry

Section - 1:
Learning Objectives:

• Describe the historical development of the atomic model )Greek, Dalton, Rutherford, Bohr(.
• Describe Rutherford's model of the atom and the evidence that support it.

Specific Objectives:
1. Compare the different models of the atom.
2. Explain how the atomic theory has changed as scientists have discovered new information about the atom.
Period -  Block 1(50 min):
Pages 17/ 18 Student Book
 Activity:
Make a model of an atom using different objects.
Preparation:

• Different objects: Bolts (B), nuts (N) tiny marbles (M),washers (W)
• Modeling clay and toothpicks
• Table for recording results of investigation (a table for each group)

Teaching Strategy

• Divide the students of the class into groups of four.
• Have students bury 3 -7 different objects in the modeling clay and make it in the form of a ball.
• he groups trade balls of clay with other group.

Ask the students:
- How many objects do you expect to find in the clay ball? Record your answer.

• Students use a broken - off toothpick as a probe to touch a hidden object. Repeat 20 times.
• Find out how many of each kind of object are in the ball, without pulling apart the clay ball.
• Students fill the following table with E, if probe hits nothing, and O, if probe hits an object. Also, write the letter of the corresponding object

Table for tecording Results

Probe hit object

Kind of object

Analysis:
Have students answer the following questions:
- How many objects did you find?
- Were you right? )Compare to table recording(
- What inference can you make about the quantity and identity of the hidden parts of the clay ball?

Conclusion:
Using indirect information we can infer the identity and the quantity of the hidden parts of a model.

Focus:
Discuss Democritus Proposition with Students.
Mention that color exists by convention, sweet and bitter by convention, but atoms and void exist in reality.
Mention to them that Democritus proposed that all matter is composed of tiny particles, called atomus, you know them as atoms.
Ask them to decide whether Democritus' theory about the atom “ matter is made up of tiny particles which are indivisible”, “ Matter is continuous” , is correct or even partly correct.
Then ask them which parts of his theory might have been changed in the 2500 years since it was first proposed.
Ask the students to give examples, from every day life, that show matter is discontinuous, using the teaching transparency T1

Teaching Transparency “Gold Atom” (T1)

Teaching Strategy
Reading Dalton's Atomic Theory (1800)
Have the students name some elements in the free form and in the combined form.

Activity:

1. Group the students in four.

- Have each group state the four postulates of Dalton's theory in their own words.

- Have the students critique each other for accuracy and clarity.

2. Refer to the diagram of different compounds )water, carbon dioxide and table salt( to show how elements combine in proportions and how the same elements always combine in the same proportions to make the same compounds.Use Teaching Transparency (T2)

• Question:

1. Give the names of the elements composing each substance and indicate how many atoms are there in each molecule. (Refer to Teaching Transparency T3)
2. “ An atom is the smallest particle into which an element can be divided and still be that element”. Is this definition still accurate? Give your opinion.

 

 

                                                                                                                                                                                                                                                 Teaching Transparency T3

Section – 1 (Continued)

Period 2 (50 min): Pages 19/ 20  Student Book

• Ask the students what is electric charge. Mention to them that there are two types of electric charge positive and negative. Objects with opposite charges attract each other, while objects with the same charge push each other away.
• Point out that:

• Have the students draw the “ Plum Pudding “ model.

 

Reading. Rutherford’s Atomic Model (1911)

Using the transparency illustrate the steps and results of Rutherford’s Gold Foil Experiment.

Teaching Transparency “Rutherford’s Gold Foil” Experiment (T4)

 

 

 

 

 

Teaching Transparency Compare Thomson’s Model and Rutherford’s Model (T5)

 

 

 

 

 

 

 

 

 

 

 

 

Focus on the Rutherford’ nuclear model of the atom.

 

• Ask the students:

• To come up with examples of things differing in size by a factor of 1000 000.
• In what part of an atom is most of its mass located?
• List two differences between atomic theory described by Thomson and that described by Rutherford.
• Draw Rutherford’s proposed planetary model of the atom. The model compares electrons to planets and the nucleus to the sun.

Bohr's Atomic Model

Teaching Transparency Bohr’s Atomic Model (1913) (T6)

 

 

 

• Point out Bohr suggested that electrons travel around the nucleus in definite paths.

• Stress that Bohr’s model was a valuable tool in predicting some atomic behavior but the atomic theory still had room for improvement.

• Point out that according to the current theory:

• Draw the attention of the students to the fact that, the more dots in the cloud the more likely an electron would be found there.

• Ask the students:

• Identify the difference in how Bohr’s theory and the modern theory describe the location of electrons.
• Draw a time line to show how the atomic theory has changed over the past several hundred years. (Draw the atomic model and associate to it the name of the scientist and the date.)
• Construct models of Thomson's plum pudding atom and Rutherford's nuclear atom Using simple materials: Cardboard, construction paper, colored pencils ,string,  cotton balls .