Physical Science

Midterm – Module 1:

Formation and Synthesis of Elements

Physical Science – Grade 11

Alternative Delivery Mode

Midterm – Module 1: Formation and Synthesis of Elements

First Edition, 2020

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Published by the Department of Education

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Undersecretary: Diosdado M. San Antonio

Development Team of the Module

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Senior High School

Physical Science

Midterm – Module 1:

Formation and Synthesis of Elements

Introductory Message

For the facilitator:

Welcome to the Physical Science for Senior High School Alternative Delivery Mode (ADM) Module on Formation and Synthesis of Elements !

This module was collaboratively designed, developed and reviewed by educators both from public and private institutions to assist you, the teacher or facilitator in helping the learners meet the standards set by the K to 12 Curriculum while overcoming their personal, social, and economic constraints in schooling.

This learning resource hopes to engage the learners into guided and independent learning activities at their own pace and time. Furthermore, this also aims to help learners acquire the needed 21st century skills while taking into consideration their needs and circumstances.

In addition to the material in the main text, you will also see this box in the body of the module:

Notes to the Teacher

This contains helpful tips or strategies that will help you in guiding the learners.

As a facilitator you are expected to orient the learners on how to use this module. You also need to keep track of the learners' progress while allowing them to manage their own learning. Furthermore, you are expected to encourage and assist the learners as they do the tasks included in the module.

For the learner:

Welcome to the Physical Science Alternative Delivery Mode (ADM) Module on Formation and Synthesis of Elements !

The hand is one of the most symbolized part of the human body. It is often used to depict skill, action and purpose. Through our hands we may learn, create and accomplish. Hence, the hand in this learning resource signifies that you as a learner is capable and empowered to successfully achieve the relevant competencies and skills at your own pace and time. Your academic success lies in your own hands!

This module was designed to provide you with fun and meaningful opportunities for guided and independent learning at your own pace and time. You will be enabled to process the contents of the learning resource while being an active learner.

This module has the following parts and corresponding icons:

What I Need to Know

This will give you an idea of the skills or competencies you are expected to learn in the module.

What I Know

This part includes an activity that aims to check what you already know about the lesson to take. If you get all the answers correct (100%), you may decide to skip this module.

What’s In

This is a brief drill or review to help you link the current lesson with the previous one.

What’s New

In this portion, the new lesson will be introduced to you in various ways such as a story, a song, a poem, a problem opener, an activity or a situation.

What is It

This section provides a brief discussion of the lesson. This aims to help you discover and understand new concepts and skills.

What’s More

This comprises activities for independent practice to solidify your understanding and skills of the topic. You may check the answers to the exercises using the Answer Key at the end of the module.

What I Have Learned

This includes questions or blank sentence/paragraph to be filled in to process what you learned from the lesson.

What I Can Do

This section provides an activity which will help you transfer your new knowledge or skill into real life situations or concerns.

Assessment

This is a task which aims to evaluate your level of mastery in achieving the learning competency.

Additional Activities

In this portion, another activity will be given to you to enrich your knowledge or skill of the lesson learned. This also tends retention of learned concepts.

Answer Key

This contains answers to all activities in the module.

At the end of this module you will also find:

References

This is a list of all sources used in developing this module.

The following are some reminders in using this module:

1. Use the module with care. Do not put unnecessary mark/s on any part of the module. Use a separate sheet of paper in answering the exercises.

2. Don’t forget to answer What I Know before moving on to the other activities included in the module.

3. Read the instruction carefully before doing each task.

4. Observe honesty and integrity in doing the tasks and checking your answers.

5. Finish the task at hand before proceeding to the next.

6. Return this module to your teacher/facilitator once you are through with it.

If you encounter any difficulty in answering the tasks in this module, do not hesitate to consult your teacher or facilitator. Always bear in mind that you are not alone.

We hope that through this material, you will experience meaningful learning and gain deep understanding of the relevant competencies. You can do it!

What I Need to Know

This module was designed and written with you in mind. It is here to help you master the basics of physical science. The scope of this module permits it to be used in many different learning situations. The language used recognizes the diverse vocabulary level of students. The lessons are arranged to follow the standard sequence of the course. But the order in which you read them can be changed to correspond with the textbook you are now using.

The module is divided into three lessons, namely:

· Lesson 1 – Formation of Heavy Elements During Star Formation and Evolution

· Lesson 2 – Synthesis of New Elements in the Laboratory

After going through this module, you are expected to:

1. Describe how heavier elements are formed during and after the stellar evolution;

2. Create a time-map or graphical timeline which shows the stages of the stellar evolution;

3. Compare the stages of stellar evolution to the stages of life;

4. Explain how the concept of atomic number led to the synthesis of new elements in the laboratory;

5. Calculate the atomic mass and atomic number of the given atom;

6. Determine the significance of things no matter how small they are.

What I Know

Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper.Comment by USER: I suggest that students must have an activity notebook. It is where they can write their answers. So the instruction might be: Write the chosen letter in your activity notebook.

1. What is the process by which nuclei combine to form a bigger and heavier nucleus?

a. evolution

b. fission

c. formation

d. fusion

2. ___________ is a form of a chemical element whose atomic nucleus contains a specific number of neutrons, in addition to the number of protons that uniquely defines the element.

a. Electron

b. Isotope

c. Neutron

d. Proton

3. This refers to the process by which a star changes over the course of time.

a. big bang

b. star formation

c. stellar evolution

d. supernova

4. ____________ is a dying star in the last stages of stellar evolution.

a. Blackhole

b. Red Giant

c. Stellar Nebula

d. White Dwarf

5. Which of the following is not a sub-atomic particle of matter?

a. electron

b. isotope

c. neutron

d. proton

6. This indicates the number of protons or electrons of an atom.

a. atomic mass

b. atomic number

c. cations

Key to answers on page 15.

d. isotopes

Lesson1Formation of Heavy Elements During Star Formation and Evolution

What’s In

During your junior high school years, you were taught about what elements are and their properties. This time, we will learn about how these elements particularly the heavy ones are formed. If the light elements – hydrogen, helium, lithium, and beryllium, were formed during the big bang nucleosynthesis, what do you think causes the formation of the heavy elements?

Comment by USER: I suggest that you change your activity. It must be designed that the parents/guardians can easily facilitate it since this is intended to be assisted by them. Also, consider contextualization/localization in this activity. Thank you, Sir.

Notes to the Parents/Guardians

Let the learner answer this!

Give a short review quiz on the elements and their properties. You may also ask them to recall some elements in the modern periodic table of elements and their symbols. It is very important that these things be recalled by them so that they will be able to connect their previously learned ideas about elements to this lesson.

What’s New

As we start this lesson, it is very important that you are familiar with the terms below. Try to open your dictionary or open your web to search the meaning or description of the following:Comment by USER: I encourage that you include in the instruction to let them write their answers on the activity notebook.

a. Nucleosynthesis

b. Protostar

c. Supernova

d. Red Giant

e. Stellar

What is It

Evolution of StarsComment by USER: I suggest if you could insert images in this section to make the module more visua. Please do not forget to cite the source of images. Thank you.

The star formation theory proposes that stars form due to the collapse of the dense regions of a molecular cloud. As the cloud collapses, the fragments contract to form a stellar core called protostar. Due to strong gravitational force, the protostar contracts and its temperature increases. When the core temperature reaches about 10 million K, nuclear reactions begin. The reactions release positrons and neutrinos which increase pressure and stop the contraction. When the contraction stops, the gravitational equilibrium is reached, and the protostar has become a main sequence star.

In the core of a main sequence star, hydrogen is fused into helium via the proton-proton chain. When most of the hydrogen in the core is fused into helium, fusion stops, and the pressure in the core decreases. Gravity squeezes the star to a point that helium and hydrogen burning occur. Helium is converted to carbon in the core while hydrogen is converted to helium in the shell surrounding the core. The star has become a red giant.

When the majority of the helium in the core has been converted to carbon, then the rate of fusion decreases. Gravity again squeezes the star. In a low-mass star (with mass less than twice the Sun’s mass), there is not enough mass for a carbon fusion to occur. The star’s fuel is depleted, and over time, the outer material of the star is blown off into space. The only thing that remains is the hot and inert carbon core. The star becomes a white dwarf.

However, the fate of a massive star is different. A massive star has enough mass such that temperature and pressure increase to a point where carbon fusion can occur. The star goes through a series of stages where heavier elements are fused in the core and in the shells around the core. The element oxygen is formed from carbon fusion; neon from oxygen fusion; magnesium from neon fusion: silicon from magnesium fusion; and iron from silicon fusion. The star becomes a multiple-shell red giant.

The fusion of elements continues until iron is formed by silicon fusion. Elements lighter than iron can be fused because when two of these elements combine, they produce a nucleus with a mass lower than the sum of their masses. The missing mass is released as energy. Therefore, the fusion of elements lighter than iron releases energy. However, this does not happen to iron nuclei. Rather than releasing energy, the fusion of two iron nuclei requires an input of energy. Therefore, elements lighter than and including iron can be produced in a massive star, but no elements heavier than iron are produced.

When the core can no longer produce energy to resist gravity, the star is doomed. Gravity squeezes the core until the star explodes and releases a large amount of energy. The star explosion is called a supernova.

How were elements heavier than beryllium formed?

Elements heavier than beryllium are formed through stellar nucleosynthesis. Stellar nucleosynthesis is the process by which elements are formed within stars. The abundances of these elements change as the stars evolve.

The origin of all the naturally occurring elements fall into two phases:

•Big Bang or Primordial Nucleosynthesis —the origin of the “light” elements; and;

•Stellar Nucleosynthesis— the origin and production of the “heavy” elements.

Nucleosynthesis is the process that creates new atomic nucleus from preexisting nucleons, which is proton neutrons. Primordial or Big Bang Nucleosynthesis refers to the process of producing the “light elements” shortly after the Big Bang.

The energy and temperature of the universe are extremely high to cause the neutrons and protons to combine and form certain species of atomic nuclei in a process called nuclear fusion. Through nuclear fusion, the light elements- Hydrogen (H), Helium (He), and small amounts of lithium (Li) and beryllium (Be) were formed. The isotopes produced during the big bang nucleosynthesis were H-1, H-2, H-3, H-4, L-7.

An isotope is a form of an element that has the same atomic number of the original element but with different atomic mass or mass number.

Origin of Heavier Elements

Heavy elements were formed only billions of years after the formation of stars. The density inside a star is great enough to sustain fusion for extended time periods required to synthesize heavy elements.

Stars are hot and dense enough to burn hydrogen-1 (1H) to helium-4 (4He). The formation of heavy elements by fusion of lighter nuclei in the interior of stars is called “stellar nucleosynthesis”.

There are many nuclear synthetic pathways or nuclear fusions to produce heavy elements:

•Carbon-Nitrogen-oxygen cycle

•Proton-proton fusion

•Triple alpha process

Layers near core of stars have very high temperatures enough to nucleosynthesize heavy elements such as silicon and iron. Elements heavier than iron cannot be formed through fusion as tremendous amounts of energy are needed for the reaction to occur. Heavy elements are formed in a supernova, a massive explosion of a star. The density inside a star is great enough to sustain fusion for extended time periods required to synthesize heavy elements.

A supernova is the explosive death of a star. In supernova, neutron capture reaction takes place, leading to formation of heavy elements. In a neutron capture reaction, heavy elements are created by addition of more neutrons to existing nuclei instead of fusion of light nuclei.

Adding neutrons to a nucleus doesn’t change an element. Rather, a more massive isotope of the same element is produced. Elements higher than iron requires tremendous amount of energy to be formed. Thus, they were produced from a neutron capture reaction in a supernova.

Pieces of Evidence

The discovery of the interstellar medium of gas and dust during the early part of the 20th century provided a crucial piece of evidence to support the star formation theory. Other pieces of evidence come from the study of different stages of formation happening in different areas in space and piecing them together to form a clearer picture.

Energy in the form of Infrared Radiation (IR) is detected from different stages of star formation. For instance, astronomers measure the IR released by a protostar and compare it to the IR from a nearby area with zero extinction. Extinction in astronomy means the absorption and scattering of electromagnetic radiation by gases and dust particles between an emitting astronomical object and an observer. The IR measurements are then used to approximate the energy, temperature, and pressure in the protostar.

What’s More

Activity 1.1

Match the terms or words on column A to their meaning or definition on column B. Write the letter of your answer in your science activity notebook.

1. Nucleosynthesisa. explosive death of a star

2. Protostarb. is a dying star in the last stages of

stellar evolution

3. Supernovac. process by which elements are formed

within stars.

4. Stellar Nucleosynthesisd. A stellar core formed by contraction of

fragments as the cloud collapses

5. Red Giante. the process that creates new atomic

nucleus from preexisting nucleons

6. Isotopesf. an element that has the same atomic

number of the original element but with different atomic mass or mass number.

g. set of reactions in nuclear astrophysics that are responsible for the creation (nucleosynthesis) of approximately half the atomic nuclei heavier than iron.

Key to answers on page 15.

Activity 1.2

Answer the following questions concisely. Write your answer in your science activity notebook.

1. How does stellar nucleosynthesis differ from primordial nucleosynthesis?

2. Give at least three examples of light elements and another three examples for heavy elements.

3. How do you compare or relate the stages of stellar evolution to the stages of life?

What I Have Learned

· Stellar nucleosynthesis is the process by which elements are formed within stars.

· The star formation theory proposes that stars form due to the collapse of the dense regions of a molecular cloud.

· A protostar is a stellar core formed when the fragments of a collapsed molecular cloud contract.

· A main sequence star is formed when gravitational equilibrium is reached during the hydrogen fusion in a protostar.

· A red giant is a star that has used up its hydrogen supply in the core and switched into the thermonuclear fusion of hydrogen in the shell surrounding the core.

· A massive star becomes a multiple-shell red giant when the elements oxygen, neon, magnesium, silicon, and iron are formed in its core together with carbon, helium, and hydrogen.

· A supernova is a star that blows apart and releases a large amount of energy.

· There are 3 reactions that led to the formation of the elements: nucleosynthesis, fusion, and neutron capture reaction. These reaction required a certain amount of energy to proceed, which was obtained from the heat of the continuously expanding universe.

· The reaction involved in the formation of these elements are dependent on the atomic mass of the elements. More energy, and thus higher temperature, is needed to form heavier elements.

· Nucleuosynthesis formed light elements, whereas fusion in stars formed elements with an atomic mass that is within the range of beryllium and iron. Thus any element with an atomic mass higher than iron, which required tremendous amount of energy to be formed was produced from a neutron capture -reaction in supernova.

· Evidence of star formation comes from studying IR emissions from the different stages of star evolution.

What I Can Do

Using your creativity, create a time map or graphical timeline of the formation of heavy elements during the star formation and evolution. Do not forget to indicate some label. Do this in a long bond paper.

AssessmentComment by USER: Will you include the answer to this to your answer key?

Modified True of False. Write T if the given statement is correct. If it is false, underline the word(s) that makes it incorrect and change it with the right one.

1. A protostar is the same with the white dwarf.

2. Supernova is the birth of a new star.

3. The star formation theory proposes that stars form due to the collapse of the dense regions of a molecular cloud.

4. A massive star becomes a multiple-shell red giant when the elements oxygen, neon, magnesium, silicon, and iron are formed in its core together with carbon, helium, and hydrogen.

5. Adding neutrons to a nucleus doesn’t change an element.

6. In the core of a main sequence star, hydrogen is fused into helium via the neutron-neutron chain.

Multiple Choice. Read and answer the following questions carefully. Write only the letter of the correct answer in your activity notebook.

1. Which of the following describes stellar nucleosynthesis?

A. It is the process by which elements are formed within stars.

B. It is the formation of elements during a supernova explosion.

C. It is the process by which elements are produced in gas clouds.

D. It is the formation of light elements such as hydrogen and helium.

2. Which of the following is a stellar core formed when the fragments of a collapsed molecular cloud contract?

A. main sequence star

B. protostar

C. red giant

D. supernova

3. Which of the following is a star that has used up its hydrogen supply in the core and switched into the thermonuclear fusion of hydrogen in the shell surrounding the core?

A. main sequence star

B. protostar

C. red giant

D. supernova

4. The formation of a star starts with the dense regions of molecular clouds.

What force pulls matter together to form these regions?

A. electromagnetic force

B. gravitational force

C. magnetic force

D. nuclear force

5. What happens when most of the hydrogen in the core is fused into helium in the stellar core?

A. Hydrogen fusion stops, and the pressure in the core decreases.

B. Nuclear energy increases until carbon and helium burning occur.

C. Hydrogen fusion continues, and the pressure in the core increases.

D. Gravity squeezes the star until helium and hydrogen burning occur.

6. Arrange the following stages of stellar evolution of a low-mass star.

A. Protostar> main sequence star> red giant> white dwarf

B. Protostar> main sequence star> white dwarf >red giant>

C. Main sequence star> protostar> red giant> white dwarf

D. Main sequence star> red giant> white dwarf> protostar

7. Which of the following is the major factor predicting the fate of a star?

A. mass of the star

B. temperature of the star

C. amount of iron produced

D. strength of gravitational force

8. Which of the following elements are not formed during stellar evolution?

A. cadmium

B. carbon

C. gold

D. oxygen

9. When does a massive star enter the stage of becoming a supernova?

A. when the silicon fusion stops

B. when the chromium fusion stops

C. when the star has burned all its oxygen

D. when the star has used up all its hydrogen fuel

10. Which of the following are true about the formation of elements lighter than iron in the core of the stars?

I. When the elements combine, they release energy which can fuel the nuclear fusion reactions in the star.

II. When the elements combine, they produce a nucleus with a mass lower than the sum of their masses.

III. When there is an input of energy from nuclear fission reactions in the star, the elements are formed.

IV. When the elements combine, they produce a nucleus with a mass greater than the sum of their masses.

A. I only

B. II only

C. I and II

D. III and IV

Additional Activities

Familiarize yourself with the chemical symbols of the different elements based on the modern periodic table. Furthermore, try to recall how to determine the atomic number and the atomic mass of the elements.

Answer Key

Assessment

Modified True or False:

1. the same – not same

2. birth – death

3. T

4. T

5. T

6. T

Multiple Choice:

1. A.

2. B

3. C

4. B

5. A

6. A

7. A9. A

8. A10. D

What's More

1. E

2. D

3. A

4. C

5. B

6. F

What I Know

1. D

2. B

3. C

4. B

5. B

6. B

What I Know

Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper.

1. It is the number of positively charged particles in an atom.

A. atomic mass

B. atomic number

C. atomic weight

D. mass number

2. He proved that the atomic number determines the major properties of an element.

A. Ernest Rutherford

B. Ernest Watson

C. Henry Gwyn-Jeffreys Moseley

D. James Chadwick

3. What was the method used by Moseley in determining the atomic number of elements?

A. mass spectrometry

B. NMR spectroscopy

C. UV spectroscopy

D. X-ray spectroscopy

4. Which of the following is true about the scientific basis of the periodic table as published by Moseley?

A. The periodic table was arranged based on the atomic weight of elements.

B. The periodic table was arranged based on the mass number of elements.

C. The periodic table was arranged based on the atomic number of elements.

D. The periodic table was arranged based on the atomic number and atomic

weights of elements.

5. How did Rutherford showed the first successful nuclear transmutation reaction?

A. He bombarded nitrogen nuclei with protons to produce oxygen nuclei.

B. He bombarded nitrogen nuclei with neutrons to produce oxygen nuclei.

C. He bombarded alpha particles of radium to nitrogen nuclei to produce

oxygen nuclei.

D. He bombarded alpha particles of nitrogen to oxygen nuclei to produce

radium nuclei.

Key to answers on page 24.

Lesson2The Atomic Number and the Synthesis of New Elements

What’s In

Do you still remember how significant determining the atomic number of an element is? Normal atoms have the same number of electrons as protons. The number of electrons is what makes each element behave a certain way in chemical reactions. So the atomic number, which is the number of protons and thus of electrons, is what makes one element different from another.

Notes to the Parents/Guardians

Let the learners prepare this!

Tell your students to secure a copy of the modern periodic table of elements with complete atomic number and atomic weight.

What’s New

To check if you can still recall about the atomic number and atomic mass of the elements, try to complete the table below by supplying the missing information.

Element

Symbol

Atomic Number

Proton

Electron

Atomic Mass

Neutron

Potassium

19

19

20

Sodium

Na

11

23

Oxygen

8

8

8

Key to answers on page 24.

Comment by USER: If possible to add images in this section for visual improvements, it will be a big help. Thank you!

What is It

Moseley’s X-ray Spectroscopy

Henry Gwyn-Jeffreys Moseley was an English physicist who demonstrated that the atomic number, the number of protons in an atom, determines most of the properties of an element. He began his study of radioactivity in Ernest Rutherford’s laboratory but later decided to explore more on X-rays.

In 1913, Moseley published a paper on the arrangement of the elements in the Periodic table based on their atomic numbers. He used X-ray spectroscopy to determine the atomic number of an element. He bombarded a beam of electrons to different elements and measured their X-ray spectral lines. His results clearly showed that frequency of the X-rays given off by an element was mathematically related to the position of that element in the Periodic table. The frequency is proportional to the charge of the nucleus, or the atomic number.

When the elements were arranged according to their atomic numbers, there were four gaps in the table. These gaps corresponded to the atomic numbers 43, 61, 85, and 87. These elements were later synthesized in the laboratory through nuclear transmutations.

Discovery of Nuclear Transmutation

In 1919, Ernest Rutherford successfully carried out a nuclear transmutation reaction — a reaction involving the transformation of one element or isotope into another element. He bombarded alpha particles from radium directed to the nitrogen nuclei. He showed that the nitrogen nuclei reacted to the alpha particles to form an oxygen nuclei. The reaction is written as

However, both alpha particles and atomic nuclei are positively charged, so they tend to repel each other. Therefore, instead of using fast-moving alpha particles in synthesizing new elements, atomic nuclei are often bombarded with neutrons (neutral particles) in particle accelerators.

The Discovery of the Missing Elements

Recall that in 1925, there were four vacancies in the periodic table corresponding to the atomic numbers 43, 61, 85, and 87. Two of these elements were synthesized in the laboratory using particle accelerators.

A particle accelerator is a device that is used to speed up the protons to overcome the repulsion between the protons and the target atomic nuclei by using magnetic and electrical fields. It is used to synthesize new elements.

In 1937, American physicist Ernest Lawrence synthesized element with atomic number 43 using a linear particle accelerator. He bombarded molybdenum (Z=42) with fast-moving neutrons. The newly synthesized element was named Technetium (Tc) after the Greek word "technêtos" meaning “artificial.” Tc was the first man-made element.

Dale Corson, K. Mackenzie

In 1940, Dale Corson, K. Mackenzie, and Emilio Segre discovered element with atomic number 85. They bombarded atoms of bismuth (Z=83) with fast-moving alpha particles in a cyclotron.

A cyclotron is a particle accelerator that uses alternating electric field to accelerate particles that move in a spiral path in the presence of a magnetic field. Element-85 was named astatine from the Greek word “astatos” meaning unstable.

The two other elements with atomic numbers 61 and 87 were discovered through studies in radioactivity. Element-61 (Promethium) was discovered as a decay product of the fission of uranium while element-87 (Francium) was discovered as a breakdown product of uranium.

Synthesis of New Elements

In the 1930s, the heaviest element known was uranium, with an atomic number 92. Early in 1940, Edwin McMillan proved that an element having an atomic number 93 could be created. He used a particle accelerator to bombard uranium with neutrons and created an element with an atomic number 93 which he named neptunium.

At the end of 1940, element-94 was synthesized by Seaborg, McMillan, Kennedy, and Wahl. They bombarded uranium with deuterons (particles composed of a proton and a neutron) in a cyclotron. Element-94 was named plutonium.

Elements with atomic numbers greater than 92 (atomic number of uranium) are called transuranium elements. Hence, neptunium and plutonium are both transuranium elements. They are unstable and decay radioactively into other elements. All of these elements were discovered in the laboratory as artificially generated synthetic elements. They are prepared using nuclear reactors or particle accelerators.

What’s More

Activity 1.1

Identification. Identify the terms or the personalities described in the following statements. Write your answers in your notebook.Comment by USER: The answers are not on the answer key.

_______________1. The heaviest element known.

_______________2. It is used to synthesize new elements.

_______________3. Elements with atomic numbers greater than 92.

_______________4. He synthesized element with atomic number 43 using a linear

particle accelerator.

_______________5. He published a paper on the arrangement of the elements in the

Periodic table based on their atomic numbers in 1913

_______________6. This is a particle accelerator that uses alternating electric field to accelerate particles that move in a spiral path in the presence of a magnetic field.

What I Have Learned

· The atomic number is the number of protons (positively charged particles) in an atom.

· Henry Gwyn-Jeffreys Moseley was an English physicist who demonstrated that the atomic number, the number of protons in an atom, determines most of the properties of an element.

· In 1919, Ernest Rutherford successfully carried out a nuclear transmutation reaction — a process of transforming one element or isotope into another element.

· In 1925, there were four vacancies in the periodic table corresponding to the atomic numbers 43, 61, 85, and 87. Elements with atomic numbers 43 and 85 were synthesized using particle accelerators.

· A particle accelerator is a device that is used to speed up the protons to overcome the repulsion between the protons and the target atomic nuclei by using magnetic and electrical fields. It is used to synthesize new elements.

· Elements with atomic numbers greater than 92 (atomic number of uranium) are called transuranium elements. They were discovered in the laboratory using nuclear reactors or particle accelerators.

What I Can Do

Answer the following questions:Comment by USER: Do not forget that in every instruction kindly include where to write their output. Consider also the place and date of submission. Thank you.

1. Why do scientists study and synthesize new transuranium elements in the laboratory? What are the uses of these elements?

2. Atoms of the elements are very tiny and invisible yet without those atoms, no matter can exist in this world. How will you relate this idea to how people should treat each other?

Assessment

Choose the letter of the best answer. Write the chosen letter on your activity notebook.Comment by USER: Should you give an answer key to this?

1. It is the number of positively charged particles in an atom.

A. atomic mass

B. atomic number

C. atomic weight

D. mass number

2. He proved that the atomic number determines the major properties of an element.

A. Ernest Rutherford

B. Ernest Watson

C. Henry Gwyn-Jeffreys Moseley

D. James Chadwick

3. What was the method used by Moseley in determining the atomic number of elements?

A. mass spectrometry

B. NMR spectroscopy

C. UV spectroscopy

D. X-ray spectroscopy

4. Which of the following is true about the scientific basis of the periodic table as published by Moseley?

A. The periodic table was arranged based on the atomic weight of elements.

B. The periodic table was arranged based on the mass number of elements.

C. The periodic table was arranged based on the atomic number of elements.

D. The periodic table was arranged based on the atomic number and atomic

weights of elements.

5. How did Rutherford showed the first successful nuclear transmutation reaction?

A. He bombarded nitrogen nuclei with protons to produce oxygen nuclei.

B. He bombarded nitrogen nuclei with neutrons to produce oxygen nuclei.

C. He bombarded alpha particles of radium to nitrogen nuclei to produce

oxygen nuclei.

D. He bombarded alpha particles of nitrogen to oxygen nuclei to produce

radium nuclei.

6. Which of the following statements is true?

A. In 1937, Ernest Lawrence synthesized technetium using a linear particle accelerator.

B. In 1925, the four vacancies in the periodic table were all synthesized in the laboratory.

C. Element-43 was discovered by bombarding molybdenum with slow-moving neutrons.

D. Element-61 and element-87 were discovered by bombarding atoms with fast-moving alpha particles.

Recall that in 1925, there were four vacancies in the periodic table corresponding to the atomic numbers 43, 61, 85, and 87.

7. Which of the following elements were produced through studies in radioactivity?

I. promethiumIII. uranium

II. franciumIV. astatine

A. I and II

B. II and III

C. II and IV

D. III and IV

8. Which of the following are true about the transuranium elements?

I. Transuranium elements were all synthesized in the laboratory.

II. Only particle accelerators can be used to synthesized transuranium elements.

III. Transuranium elements are elements which have atomic numbers greater than 92.

IV. Some examples of transuranium elements include uranium, plutonium, and neptunium.

A. I nd II

B. II and III

C. III and IV

D. I,II,III and IV

9. Which of the following is true about the particle accelerators?

I. They use both magnetic and electrical fields to speed up protons.

II. They use both magnetic and electrical fields to speed up electrons.

III. They speed up the protons, overcoming the repulsion between the protons and target nuclei.

IV. They speed up electrons, overcoming the repulsion between the neutrons and target nuclei.

A. I and II

B. II and III

C. III and IV

D. I and III

10. Why is it easier to use neutrons to synthesize new elements compared to alpha particles?

A. Neutrons are negatively charged. Thus, they are strongly attracted to the positively charged target nuclei.

B. Neutrons have no charge. Thus, there is no electrostatic repulsion between them and the target nuclei.

C. Neutrons are positively charged. Thus, they are able to overcome the electrostatic repulsion between the target nuclei.

D. Neutrons are neither positively charged or negatively charged. Thus, they do not require force to collide with the target nuclei.

Additional Activities

Research on the latest instruments used in preparing new elements in the laboratory. What were the instruments used in preparing the newest four elements, nihonium, moscovium, tennessine, and oganesson?

Answer Key

Assessment

1. B.10. B.

2. C.

3. D.

4. C.

5. C.

6. A.

7. A.

8. D.

9. A

What's More

1. Uranium

2. Particle Accelerator

3. Transuranium

4. Ernest Lawrence

5. Henry Moseley

6. cyclotron

What I Know

1. B

2. C.

3. D.

4. C.

5. C.

References

Websites:

Bigael, J. (2017, September 9). Formation of Light and Heavy Elements. https://www.slideshare.net/JeromeJerome1/formation-of-light-and-heavy-elements#:~:text=Heavy%20elements%20are%20formed%20in,massive%20explosion%20of%20a%20star.&text=Rather%2C%20a%20more%20massive%20isotope,capture%20reaction%20in%20a%20supernova.

Canoy, W. (2017, November 4). The Formation of Heavier Elements during Star Formation and Evolution. https://www.facebook.com/notes/physical-science/lesson-12-the-formation-of-heavier-elements-during-star-formation-and-evolution/1880966238586259/

Russell, R. (2009, August 26). Atomic Number. https://www.windows2universe.org/physical_science/physics/atom_particle/atomic_number.html#:~:text=Why%20is%20the%20atomic%20number,one%20element%20different%20from%20another.

Canoy, W. (2017, November 4). The Atomic Number and the Synthesis of New Elements. https://www.facebook.com/notes/physical-science/lesson-27-the-atomic-number-and-the-synthesis-of-new-elements/1881067791909437

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