This is the Physical Science Quarter 1, Module 1 self-learning module for Senior High School (Grade 11/12), an Alternative Delivery Mode (ADM) module from DepEd National Capital Region (First Edition, 2020). It covers how heavier elements form as stars are born and evolve, and how new elements are made in the laboratory. After the module, learners should be able to explain each stage of a star’s life and name the elements it produces.
What learners will learn
The module has one lesson, “Formation of Elements During Stellar Formation and Evolution.” After going through it, learners are expected to:
- Describe the formation of heavier elements during the formation and evolution of stars.
- Cite astronomical evidence which justifies the formation of elements during stellar formation and evolution.
- Appreciate the importance of the discovery of atomic number, which led to the synthesis of new elements in the laboratory.
The life of a star and the elements it makes
The module starts with the star formation theory: stars form when a dense region of a molecular cloud collapses. From there, a star goes through these stages:
- Protostar: Fragments of the cloud contract and form a stellar core. Contraction and gravity raise the temperature, and nuclear reactions begin when it reaches 10 million Kelvin.
- Main sequence star: It forms when contraction stops and the protostar reaches gravitational equilibrium. In the core, the two primordial elements, hydrogen and helium, fuse.
- Red giant: Helium is converted to carbon in the core, while hydrogen is converted to helium in the layer around the core. Massive stars have enough energy, mass, temperature, and pressure to fuse heavier elements in shells around the core.
- White dwarf: In low-mass stars, the energy is not enough to keep the reaction going. The outer material is blown off, leaving an inert carbon core.
- Supernova: The core can no longer produce the energy needed to resist gravity, so the star explodes and releases a large amount of energy.
The module calls this process stellar nucleosynthesis: heavier elements such as beryllium and iron form by combining protons and neutrons from the nuclei of lighter elements. It is the second cosmological event after the first three minutes of the Big Bang, when the first three elements formed.
Fusion reactions shown in the module
| Reaction | Product |
|---|---|
| Helium + carbon | Oxygen and gamma rays |
| Helium + oxygen | Neon and gamma rays |
| Carbon + carbon | Magnesium and gamma ray |
| Oxygen + oxygen | Silicon, an alpha particle (helium), and gamma rays |
In massive stars, the module also lists a chain that ends at iron: carbon from helium fusion, neon from oxygen fusion, magnesium from neon fusion, silicon from magnesium fusion, and iron from silicon fusion. Stars build heavier elements from lighter ones, but not past iron (atomic number 26).
Evidence and new elements in the laboratory
The module gives two pieces of evidence for stellar nucleosynthesis and the star formation theory:
- The discovery of interstellar dust and gases, which shows the stages of star formation happening across the universe.
- Infrared radiation given off during star formation, a sign that nucleosynthesis happens alongside a star’s formation and evolution.
It then explains the role of atomic number. English chemist Henry Moseley arranged the periodic table by atomic number, which equals the number of protons. This let scientists predict elements, since adding a proton to an element raises its atomic number and forms a new element.
The module describes three nuclear reactions:
- Alpha emission: A particle with two protons and two neutrons is emitted, producing a lighter new element (uranium-238 becomes thorium-234).
- Beta emission: A neutron becomes a proton and an electron is ejected, producing a new element with the same mass (iodine-131 becomes xenon-131).
- Gamma emission: A gamma ray is emitted from a nucleus in an excited state (barium-137 stays barium-137).
Activities in the module
- What I Know: a 15-item multiple-choice pretest.
- What’s In: a table review of how primordial elements (deuterium, tritium, helium, lithium) form.
- What’s New: a “Stellar Word Puzzle” of star and element terms.
- What’s More: Activity 1 “Stellar Products” (predicting helium fusion products), Activity 2 “Birth from the Stars” (elements formed at each star stage), and Activity 3 “It’s Okay Decay” (naming the type of nuclear reaction and its product).
- What I Can Do: eight essay questions, such as comparing elements formed by small and massive stars.
- Assessment: a 15-item multiple-choice post-test.
- Additional Activities: writing balanced alpha, beta, and gamma decay reactions for uranium-235, uranium-238, carbon-14, and barium-137.
How to use this module
- Learners: Answer What I Know first. If you get every item right, the module says you may skip it. Then work through each part in order, finishing one task before the next. Write your answers on a separate sheet, not on the module, and check your What’s More work with the answer key at the end. Return the module to your teacher when you are done.
- Parents: Encourage your child to read each instruction carefully and to check answers honestly. Contact the teacher if your child has trouble with a task.
- Teachers: Orient learners on using the module, track their progress, and use the Notes to the Teacher boxes for guidance. Give positive feedback as learners work toward mastery.
Frequently asked questions
What grade and quarter is this Physical Science module for?
It is for Senior High School Physical Science (Grade 11/12), Quarter 1, Module 1.
How many lessons does the module have?
It has one lesson: Formation of Elements During Stellar Formation and Evolution.
What is stellar nucleosynthesis?
The module defines it as the process by which elements are formed within a star during its formation and evolution, by combining protons and neutrons from the nuclei of lighter elements.
Does the module have an answer key?
Yes. The answer key at the end covers the pretest, the What’s More activities, the Additional Activities, and the Assessment.
Who arranged the periodic table by atomic number?
The module credits English chemist Henry Moseley, whose arrangement by atomic number helped scientists predict and synthesize new elements.
Full text of the module
The text below is a transcription of the PDF above, as printed.
Physical Science Quarter 1 – Module 1: Exploring the Formation of Elements During Stellar Formation and Evolution
Senior High School
[illustration: learners studying under a tree and at a desk with a teacher, a globe, and a lamp]
ALTERNATIVE DELIVERY MODE
GOVERNMENT PROPERTY NOT FOR SALE
Physical Science Alternative Delivery Mode Quarter 1 – Module 1: Exploring the Formation of Elements During Stellar Formation and Evolution First Edition, 2020
Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for the exploitation of such work for a profit. Such agency or office may, among other things, impose as a condition the payment of royalties.
Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this module are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them.
Published by the Department of Education Secretary: Leonor Magtolis Briones Undersecretary: Diosdado M. San Antonio
Development Team of the Module
Authors: Beverly Joy O. Lorenzo
Editors: Joey H. Villanueva, Arlene C. Malaybalay
Reviewers: Tommy R. Rico, Emiterio D. Macarubbo, Maricris N. Surigao
Illustrator: Daniel A. Lorenzo
Layout Artist: Justine C. Montoya
Management Team: Wilfredo E. Cabral, Director IV Jennifer Vivas, CLMD Chief Dennis M. Mendoza, Regional EPS in-charge of LRMS Micah S. Pacheco, Regional ADM Coordinator Jocelyn M. Aliñab, CID Chief Tommy R. Rico, Division in-charge of LRMS and Division ADM Coordinator
Department of Education – National Capital Region
Office Address: Misamis St., Bago Bantay, Quezon City
Telefax: 02-929-0153
E-mail Address: depedncr@deped.gov.ph
Senior High School
Physical Science Quarter 1 – Module 1: Exploring the Formation of Elements During Stellar Formation and Evolution
[transcriber’s note: this page repeats the module title from the cover, with the DepEd logo]
Introductory Message
For the facilitator:
Welcome to the Physical Science Grade 11/12 Alternative Delivery Mode (ADM) Module with the topic on formation of heavier elements during star formation and evolution, and synthesis of new elements in the laboratory!
This module was collaboratively designed, developed, and reviewed by educators 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 in 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:
[illustration: clipboard icon]
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 11/12 Alternative Delivery Mode (ADM) Module with the topic on formation of heavier elements during star formation and evolution, and synthesis of new elements in the laboratory!
Our hands are one of the most symbolized parts 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 able to process the contents of the learning resource while being an active learner.
This module has the following parts and corresponding icons:
| Part | Description |
|---|---|
| What I Need to Know | This will give you an idea of the skills or competencies you are expected to learn inthe module. |
| What I Know | This part includes an activity that aims to check what you already know about the lessons. 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 ofthe 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 sentences/paragraphs to be filled in to process what you learned from the lesson. |
[transcriber’s note: table continued from the previous page]
| Part | Description |
|---|---|
| What I Can Do | This section provides an activity that will help you transfer your new knowledge or skill I 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:
| Part | Description |
|---|---|
| References | This is a list of all sources used in developing this module. |
The following are some reminders in using this module:
- 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.
- Don’t forget to answer What I Know before moving on to the other activities included in the module.
- Read the instruction carefully before doing each task.
- Observe honesty and integrity in doing the tasks and checking your answers.
- Finish the task at hand before proceeding to the next.
- 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 a 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 to help you master the formation of heavier elements during star formation and evolution, and synthesis of new elements in the laboratory. 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.
The module consists of one lesson only:
- Lesson 1 – Formation of Elements During Stellar Formation and Evolution
After going through this module, you are expected to:
- Describe the formation of heavier elements during the formation and evolution of stars;
- Cite astronomical evidence which justifies the formation of elements during stellar formation and evolution;
- Appreciate the importance of the discovery of atomic number which led to the synthesis of new elements in the laboratory.
Notes to the Teacher This module provides learning activities which encourage self-directed learning. Moreover, your role is to facilitate the learning process by providing a clear understanding on how to maximize the use of this module, monitor the development of our learners, scaffold the acquisition of learning to achieve target mastery level and provide positive feedbacks regarding their progress.
What I Know
DIRECTIONS: Read each question carefully. Choose the letter of the best answer. Write your answer on a separate sheet of paper.
- Which of the following asserts that stars are formed when a dense region of molecular cloud collapse?
- a. Big Bang Theory
- b. Evolution Theory
- c. Creation Theory
- d. Star Formation Theory
- Which refers to the fragments of clouds that contract and form a stellar core?
- a. Protostar
- b. Red giant
- c. Supernova
- d. White dwarf
- What will be formed when a protostar attains its gravitational equilibrium?
- a. Main sequence star
- b. Red Giant
- c. Supernova
- d. White dwarf
- Where do hydrogen and helium fuse in a main sequence star?
- a. Core
- b. Crust
- c. Inner core
- d. Mantle
- Helium will be converted into what after its fusion with two more helium atoms?
- a. Argon
- b. Carbon
- c. Chlorine
- d. Oxygen
- When a star has used up all the hydrogen in its core, hydrogen will be converted into helium in the layer immediately surrounding the core. What stage of star formation is this?
- a. Protostar
- b. Red giant
- c. Supernova
- d. White dwarf
- During red giant formation, what element will be produced by the fusion of oxygen with helium?
- a. Helium
- b. Hydrogen
- c. Neon
- d. Silicon
- During red giant formation, what element will be produced by the fusion of neon with helium?
- a. Carbon
- b. Magnesium
- c. Manganese
- d. Silicon
- During red giant formation, what element will be produced by the fusion of silicon with another silicon atom?
- a. Argon
- b. Boron
- c. Iron
- d. Gold
- At what stage does the outer covering of a star blow due to insufficient energy?
- a. Protostar
- b. Red giant
- c. Supernova
- d. White dwarf
- What will happen to a star if its core can no longer produce the needed energy?
- a. Protostar
- b. Red giant
- c. Supernova
- d. White dwarf
- Who predicted new elements based on the atomic number of known elements?
- a. Ernest Rutherford
- b. John Newlands
- c. Henry Mosely
- d. Plato
- What type of nuclear reaction emits a particle with two protons and two neutrons?
- a. Alpha emission
- b. Beta emission
- c. Gamma emission
- d. Fusion
- What type of nuclear reaction emits electrons?
- a. Alpha emission
- b. Beta emission
- c. Gamma emission
- d. Fission
- What type of nuclear reaction emits gamma rays?
- a. Alpha emission
- b. Beta emission
- c. Gamma emission
- d. Fusion
1 Formation and Synthesis of Heavier Elements
“In one of the most inhospitable places in our galaxy, stars have prevailed. It appears that star formation is much more tenacious than we previously believed.”
-Sergei Nayakshin
What’s In
DIRECTIONS: Demonstrate understanding of primordial elements formation by completing the table below.
| Elements | Reactants 1 | Reactants 2 | Nuclear Reaction |
|---|---|---|---|
| Deuterium | |||
| Tritium | |||
| Helium (Stable) | |||
| Lithium |
What’s New
Stellar Word Puzzle
Directions: Encircle and write down the words which are related to star and element formation. In addition, expand your vocabulary by finding the meaning of the encircled words and relate them to your prior knowledge.
| N | U | C | L | E | O | S | Y | N | T | H | E | S | I | S | G | B | E | T | A |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| S | D | A | J | L | H | Y | D | R | O | G | E | N | A | L | P | H | A | I | I |
| T | U | T | H | E | L | I | U | M | S | U | N | S | T | A | B | L | E | A | B |
| A | S | O | R | M | N | U | C | L | E | U | S | N | U | C | L | E | I | D | T |
| R | T | M | D | E | F | U | S | I | O | N | R | A | D | I | A | T | I | O | N |
| C | O | C | H | N | F | I | S | S | I | O | N | G | A | M | M | A | S | G | N |
| F | I | V | R | T | P | R | O | T | O | S | T | A | R | M | H | D | R | S | V |
| H | F | L | F | S | U | P | E | R | N | O | V | A | G | J | D | H | T | A | C |
What is It
Evolution of Stars and the Formation of Heavier Elements
Star formation theory states that stars are formed when a dense region of molecular cloud collapses. During this process, fragments of clouds contract and form a stellar core known as protostar. The contraction and gravitational force of the protostar result in an increase in temperature which triggers nuclear reaction within the star upon reaching 10 million Kelvin. Throughout the reaction, neutrinos and positrons are released, slowing down the reaction. Once the contraction stops and the protostar attains its gravitational equilibrium, a main sequence star will be formed.
[chart: diagram of concentric rings; Labels as printed: INNER IRON CORE; NON BURNING HYDROGEN; HYDROGEN FUSION; HELIUM FUSION; CARBON FUSION; OXYGEN FUSION; NEON FUSION; MAGNESIUM FUSION; SILICON FUSION. Values are not labeled on the chart.]
In the core of a main sequence star, hydrogen fuses with helium through proton-proton chain. In addition, the gravitational force of a main sequence star forces hydrogen and helium to fuse resulting to burning of the 2 primordial elements. Furthermore, at this stage, helium is converted to carbon at the core while hydrogen is converted into helium surrounding the core which denotes the formation of red giant. On the other hand, since massive stars possess enough energy, mass, temperature, and pressure, the star will undergo a series of stages where heavier elements are fused around the shell of the core whereas carbon will be formed through helium fusion, neon will be formed through oxygen fusion, magnesium from neon fusion, silicon from magnesium fusion, and iron from silicon fusion which denotes the formation of red giant.
Considering that the majority of helium surrounding the core has been converted into carbon, the rate of reaction will decrease causing the gravitational force to act squeezing the entire star. With low mass stars, considering that the amount of energy is not enough to sustain the reaction, and that the star’s fuel has been exhausted, the outer material covering the star will eventually be blown-off leaving an inert carbon core resulting to the formation of white dwarf.
The first 3 minutes of Big Bang focused primarily on the expansion and cooling of universe so as to the synthesis of the first three elements. On the other hand, the second cosmological event is Stellar nucleosynthesis, a process in which heavier elements such as Beryllium (₄Be) and Iron (₂₆Fe) were formed by combining protons and neutrons from the nuclei of a lighter elements.
Moreover, under the process of stellar nucleosynthesis, heavier elements are created in different types of stars as they die or explode and the abundance of these elements change as the stars evolve.
Stable Helium reacts with Carbon to produce oxygen and gamma rays under extreme gravitational force and temperature. Oxygen as the product of the initial reaction then reacts with Helium to form Neon and gamma rays (⁴₂He + ¹⁶₈O → ²⁰₁₀Ne + ⁰₀γ). The third reaction involves carbon reacting with another Carbon forming Magnesium and gamma ray (¹²₆C + ¹²₆C → ²⁴₁₂Mg + ⁰₀γ). On the other hand, Oxygen to Oxygen fusion will create Silicon, alpha particle (Helium) and gamma rays as product. (¹⁶₈O + ¹⁶₈O → ²⁸₁₄Si + ⁴₂He + ⁰₀γ). The process will continue to form heavier elements from lighter ones, but not heavier than Iron with atomic mass of 26. Lastly, supernova happens when the core can no longer produce the needed energy to resist gravitational force, leading to its explosion and release of large amounts of energy.
Pieces of Evidence
One remarkable evidence to support stellar nucleosynthesis and star formation theory is the discovery of interstellar dusts and gasses which justifies the stages of stellar formation which are happening across the universe. In addition, infrared radiation being emitted in the process of stellar formation serves as a strong indication that stellar nucleosynthesis is a concurrent with stellar formation and evolution.
Atomic Number and Synthesis of New Elements
Throughout history, scientist have been working on a periodic organization of elements as to their properties and to predict new elements. This is because understanding the properties of these known elements will provide them a pattern which would help them discover new elements. Henry Gwyn Jeffreys Mosely an English chemist arranged the elements in the periodic table by using atomic number as basis. This allowed him to identify and predict any element considering the number of protons which is equal to the atomic number. In addition, he emphasized that adding proton to an element increases its atomic number and that new element will be formed.
Nuclear Reaction
Alpha Emission: a particle with two protons and two neutrons is emitted resulting to a lighter new element. ²³⁸₉₂U → ²³⁴₉₀Th + ⁴₂He
Beta Emission: a neutron becomes a proton, and an electron will be ejected resulting to a new element with the same mass. ¹³¹₅₃I → ¹³¹₅₄Xe + ⁰₋₁e
Gamma Emission: gamma ray will be emitted when a radioactive nuclide leaves a nucleus in an excited state. ¹³⁷₅₆Ba → ¹³⁷₅₆Ba + γ-photon.
What’s More
Activity 1 Stellar Products
Directions: Based on your understanding about the formation of heavier elements during stellar nucleosynthesis, predict the reactants, and products which will be formed by the following reactions inside the table.
| Reactant 1 | Reactant 2 | Atomic # of Reactant 2 | Mass # of Reactant 2 | Chemical Equation | Product |
|---|---|---|---|---|---|
| Helium | Oxygen | ||||
| Helium | Neon | ||||
| Helium | Magnesium | ||||
| Helium | Silicon | ||||
| Helium | Sulfur | ||||
| Helium | Argon | ||||
| Helium | Calcium | ||||
| Helium | Titanium |
Activity 2 Birth from the Stars
Directions: Identify the elements formed during the following stages of star formation and evolution.
| Stages | What were the elements formed? | How were these elements formed? |
|---|---|---|
| Protostar | ||
| Main Sequence Star | ||
| Red Giant Star | ||
| White Dwarf | ||
| Supernova |
Activity 3 It’s Okay Decay
Directions: Determine the type of chemical reaction in each item (a-emission, b-emission, y-emission, fission, fusion). In addition, write the product of the following chemical reactions on the space provided for product side.
_____ 1. ₁₅³²P → ₁₆³²S + _____
_____ 2. ₉₂²³⁸U → ₉₀²³⁴Th + _____
_____ 3. ₉₀²³⁴Th → ₉₀²³⁴Th + _____
_____ 4. ₅₃¹³¹I → ₅₄¹³¹Xe + _____
_____ 5. ₈₈²²⁶Ra → ₈₆²²²Rn + _____
[transcriber’s note: the circled arrow symbol between each reactant and product is printed as a solid arrow icon]
What I Have Learned
- Gamma Ray is electromagnetic radiation with a relatively short wavelength emitted during gamma decay and other reactions.
- Radio Active Nuclei refers to an unstable nucleus that spontaneously emits particles and energy throughout the radioactive decay process.
- Supernova is a star that blows apart and releases a large amount of energy.
- Star formation theory proposes that stars were formed due to the collapsing of a dense region of molecular clouds.
- Stellar nucleosynthesis refers to the process by which elements are formed within the star during star formation and evolution.
What I Can Do
Directions: Based on your understanding of this module, analyze and answer the following questions regarding element formation during star formation and synthesis of new elements in the laboratory.
- Describe the formation of primordial elements during the early stage of stellar formation and evolution.
- Compare and contrast the elements formed by a small star and a massive star.
- Describe the role being played by gravitational force in the creation of new elements.
- Discuss the pieces of evidence used by scientists to explain the formation of heavier elements during stellar formation and evolution.
- How did the discovery of atomic number revolutionize how we view the periodic table of elements as a tool in predicting new elements?
- Describe how elements in the laboratory are synthesized.
- Discuss how the elements formed in the star reached distant places/galaxies?
- How did the discovery of atomic number pave the way to the synthesis of new elements in the laboratory?
Assessment
Directions: Read each question carefully. Choose the letter of the best answer. Write your answer on a separate sheet of paper.
When helium atoms fuse, Helium will be converted to _____.
- a. Argon
- b. Carbon
- c. Chlorine
- d. Oxygen
_____ will be formed when protostar attains its gravitational equilibrium.
- a. Main sequence star
- b. Red Giant
- c. Supernova
- d. White dwarf
Hydrogen and helium fuse at the _____ of a main sequence star.
- a. Core
- b. Crust
- c. Inner core
- d. Mantle
_____ will be produced by silicon fusion during red giant formation.
- a. Argon
- b. Boron
- c. Iron
- d. Gold
_____ predicted new elements based on the atomic number of known elements.
- a. Ernest Rutherford
- b. John Newlands
- c. Henry Mosely
- d. Plato
_____ will be produced by oxygen fusion during red giant formation.
- a. Helium
- b. Hydrogen
- c. Neon
- d. Silicon
During the formation of a _____ hydrogen will be converted into helium in the layer surrounding the core.
- a. Protostar
- b. Red giant
- c. Supernova
- d. White dwarf
_____ states that stars are formed when a dense region of molecular cloud collapse.
- b. Big Bang Theory
- c. Creation Theory
- c. Evolution Theory
- d. Star formation Theory
[transcriber’s note: the option labels for item 8 are printed as b., c., c., d.; the first option has no label]
Two protons and two neutrons will be emitted during _____ decay.
- a. Alpha
- b. Beta
- c. Gamma
- d. Fusion
_____ will happen to a star if its core can no longer produce the needed energy.
- a. Protostar
- b. Red giant
- c. Supernova
- d. White dwarf
_____ will be produced by neon fusion during red giant formation.
- a. Carbon
- b. Magnesium
- c. Manganese
- d. Silicon
Gamma ray will be emitted during _____ decay.
- a. Alpha
- b. Beta
- c. Gamma
- d. Fusion
When the fragments of clouds contract, a stellar core known as _____ is formed.
- a. Protostar
- b. Red giant
- c. Supernova
- d. White dwarf
Electron will be emitted during _____ decay.
- a. Alpha
- b. Beta
- c. Gamma
- d. Fission
During _____ stage the outer covering of star will blow due to insufficient energy.
- a. Protostar
- b. Red giant
- c. Supernova
- d. White dwarf
Additional Activities
Directions: Write the balanced nuclear reaction of the following elements under alpha, beta and gamma decay.
| ELEMENT | RADIO ACTIVE DECAY | BALANCED CHEMICAL REACTION |
|---|---|---|
| Uranium 235 | ALPHA DECAY | |
| BETA DECAY | ||
| GAMMA DECAY |
| ELEMENT | RADIO ACTIVE DECAY | BALANCED CHEMICAL REACTION |
|---|---|---|
| Uranium 238 | ALPHA DECAY | |
| Carbon 14 | BETA DECAY | |
| Barium 137 | GAMMA DECAY |
Answer Key
[transcriber’s note: the answer key is printed rotated upside down in a small image; the entries below were read from it, and any entry marked [?] is uncertain]
What’s More
Activity 1 Stellar Products
| Reactant 2 | A # | M # | Chemical Equation | Product |
|---|---|---|---|---|
| Oxygen | 16 | 8 | ⁴₂He + ¹⁶₈O → ²⁰₁₀Ne | ²⁰₁₀Ne |
| Neon | 20 | 10 | ⁴₂He + ²⁰₁₀Ne → ²⁴₁₂Mg | ²⁴₁₂Mg |
| Magnesium | 24 | 12 | ⁴₂He + ²⁴₁₂Mg → ²⁸₁₄Si | ²⁸₁₄Si |
| Silicon | 28 | 14 | ⁴₂He + ²⁸₁₄Si → ³²₁₆S | ³²₁₆S |
| Sulfur | 32 | 16 | ⁴₂He + ³²₁₆S → ³⁶₁₈Ar | ³⁶₁₈Ar |
| Argon | 36 | 18 | ⁴₂He + ³⁶₁₈Ar → ⁴⁰₂₀Ca | ⁴⁰₂₀Ca |
| Calcium | 40 | 20 | ⁴₂He + ⁴⁰₂₀Ca → ⁴⁴₂₂Ti | ⁴⁴₂₂Ti |
| Titanium | 44 | 22 | ⁴₂He + ⁴⁴₂₂Ti → ⁴⁸₂₄Cr | ⁴⁸₂₄Cr |
[transcriber’s note: the column headings are printed in the key as “A #” and “M #”; the Product column entries are read from the equations and marked [?] where not clearly printed]
Activity 3 It’s Okay Decay
- Beta decay: ₁₅³²P → ₁₆³²S + ₋₁⁰e
- Alpha decay: ₉₂²³⁸U → ₉₀²³⁴Th + ₂⁴He
- Gamma decay: ₉₀²³⁴Th → ₉₀²³⁴Th + γ
- Beta decay: ₅₃¹³¹I → ₅₄¹³¹Xe + ₋₁⁰e
- Alpha decay: ₈₈²²⁶Ra → ₈₆²²²Rn + ₂⁴He
Additional Activities
- Uranium 235, alpha decay: ₉₂²³⁵U → ₉₀²³¹Th + ₂⁴He [?]
- Uranium 235, beta decay: ₉₂²³⁵U → ₉₃²³⁵Np + ₋₁⁰e [?]
- Uranium 235, gamma decay: ₉₂²³⁵U → ₉₂²³⁵U + γ [?]
- Uranium 238, alpha decay: ₉₂²³⁸U → ₉₀²³⁴Th + ₂⁴He [?]
- Carbon 14, beta decay: ₆¹⁴C → ₇¹⁴N + ₋₁⁰e [?]
- Barium 137, gamma decay: ₅₆¹³⁷Ba → ₅₆¹³⁷Ba + γ [?]
What I Know
- D
- A
- C
- A
- B
- B
- C
- B
- C
- D
- A
- C
- A
- B
- C
[transcriber’s note: these answers are read from the rotated key image and should be checked against the original]
Assessment
- B
- A
- A [?]
- C
- C
- C
- B
- D
- A
- C
- B
- C
- A
- B
- C [?]
References
Bayo-ang, Roly., Coronacion, Maria Lourdes., Jorda, Annamae., & Restubog, Anna Jamille. Physical Science for Senior High School (1st edition). Quezon City: Educational Resources Corporation, 2017.
For inquiries or feedback, please write or call:
Department of Education – Bureau of Learning Resources (DepEd-BLR)
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Email Address: blr.lrqad@deped.gov.ph * blr.lrpd@deped.gov.ph
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