8
SCIENCE
Quarter 3 - Module 3
Atomic Structure
Science — Grade 8
Alternative Delivery Mode
Quarter 3 – Module 3: Atomic Structure
First Edition, 2020
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Published by the Department of Education – Division of Gingoog City
Division Superintendent: Jesnar Dems S. Torres, PhD, CESO VI
Development Team of the Module
Writer(s):
Susan S. Balighot
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Florida D. Arias, PhD, PSDS
Dahlia M. Maputol
Illustrator(s):
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Schools Division Superintendent
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Pablito B. Altubar
CID Chief
Members:
Nilda U. Villegas, EPS – Science
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8
SCIENCE
Quarter 3 - Module 3
Atomic Structure
This page is intentionally blank.
Table of Contents
What This Module is About .................................................................................................... i
What I Need to Know ............................................................................................................. i
How to Learn from this Module ..............................................................................................ii
Icons of this Module ...............................................................................................................ii
What I Know (Pre-Test)......................................................................................................... iii
Determining the Number of Protons, Neutrons, and Electrons in a Particular Atom .............. 1
What’s In ........................................................................................................................... 1
Activity 1: Draw Me! ....................................................................................................... 1
Activity 2: Transferring Charges ..................................................................................... 2
What I Need to Know......................................................................................................... 2
What’s New ....................................................................................................................... 3
Activity 3: The Protons, Neutrons and Electrons ............................................................ 3
Activity 4: What’s the difference? ................................................................................... 3
Activity 5: Complete Me ................................................................................................. 4
What Is It ........................................................................................................................... 5
What’s More ...................................................................................................................... 6
Activity 6: The PEN ........................................................................................................ 6
Activity 7 – Atomic Structure .......................................................................................... 7
What I Have Learned......................................................................................................... 8
Activity 8: Try Again! ...................................................................................................... 8
What I Can Do ................................................................................................................... 9
Activity 9: THIS IS IT! ..................................................................................................... 9
Summary ............................................................................................................................ 10
Assessment (Post-Test) ...................................................................................................... 11
Key to Answers ................................................................................................................... 12
References ......................................................................................................................... 14
This page is intentionally blank.
What This Module is About
On New Year’s Eve, you will never miss the colorful bursts of bright silver, red, green,
and blue lights sparkling right in your front yard. The spectacular colors of fireworks are
characteristics of the light- emitting elements. Scientist have proven that atom is composed of
even smaller particles. Matter is made up of atoms and molecules. Atom is the smallest
particle of an element that can exist. It has the ability to enter chemical reaction. Knowledge
about the structure of the atom has been applied to certain purpose, example in medicine.
You need to learn more about the subatomic particles the protons, electrons, and neutrons
that interact in many materials.
In this module, you will learn about how to determine the number of protons, electrons
and neutrons.
What I Need to Know
At the end of this module, you should be able to:
1. Determine the number of protons, neutrons, and electrons in a particular atom.
(S8MT-IIIe-f-10)
i
How to Learn from this Module
To achieve the objectives cited above, you are to do the following:
• Take your time reading the lessons carefully.
• Follow the directions and/or instructions in the activities and exercises diligently.
• Answer all the given tests and exercises.
Icons of this Module
What I Need
to Know
This part contains learning objectives that are
set for you to learn as you go along the module.
What I Know
This is an assessment as to your level of
knowledge to the subject matter at hand, meant
specifically to gauge prior related knowledge.
What’s In
This part connects previous lesson with that of
the current one.
What’s New
An introduction of the new lesson through
various activities, before it will be presented to
you.
What Is It
These are discussions of the activities as a way
to deepen your discovery and understanding of
the concept.
What’s More
These are follow-up activities that are intended
for you to practice further in order to master the
competencies.
What I Have
Learned
Activities designed to process what you have
learned from the lesson.
What I Can
Do
These are tasks that are designed to showcase
your skills and knowledge gained, and applied
into real-life concerns and situations.
ii
What I Know (Pre-Test)
Directions: Read and answer the questions below. Write the letter of the correct
your activity notebook.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
answer in
If you comb our hair and the comb becomes positive charged, what will happen to
your hair?
A. It will remain uncharged
C. It will become positively charged
B. It will be repelled by the com
D. It will become negatively charged
Which of the following describe atoms best?
A. Are found only in solid
C. Were first found in ants
materials
B. Smallest particle
D. Contain proton and neutron
What is the atomic mass of an element with 1 proton, 1 electron, and 0 neutron?
A. 1
C. 3
B. 2
D. 4
What is the atomic mass of an element with 40 protons,40 electrons and 46 neutrons?
A. 80
C. 6
B. 86
D. 40
What particle determine the atomic number of the atom?
A. Neutron
C. Proton
B. Quark
D. Atomic Mass
Determine the protons and electrons in Calcium atom? (atomic number is 20)
A. 20; 20
C. 20; 10
B. 40; 20
D. 20; 40
Which of the following has a negative charge?
A. Protons
C. Neutrons
B. Electrons
D. Mass number
An atom with four electrons, four protons, and five neutrons has an atomic number of?
A. 4
C. 8
B. 5
D. 9
What are neutrons?
A. Positively charged particles
C. Particles with zero electric charge
B. Particles of negligible mass
D. Particles with charge numerically
opposite in sign to that of
electrons
What is the number of protons in a Uranium atom? (atomic number = 92)
A. 82
C. 72
B. 92
D. Cannot be determined
iii
Lesson Determining the Number of
1
Protons, Neutrons, and
Electrons in a Particular Atom
What’s In
Activity 1: Draw Me!
Directions: Draw inside the box the arrangement of atoms and molecules. Write your answer
in your Science journal.
Aluminum
(Solid)
Mercury
(Liquid)
Hydrogen
(Gas)
Q1.
What phase of matter illustrated in aluminum? Mercury? Hydrogen?
________________________________________________________________
Q2.
How many kinds of atom/s are found in aluminum? ______
Mercury? ________
Hydrogen? _________
Q3.
Describe the arrangement of atoms in each of the elements.
________________________________________________________________
________________________________________________________________
1
Activity 2: Transferring Charges
Objectives: After doing this activity, you should be able to:
1. 1.observe that object will attract or repel each other.
2. infer that objects may gain positive or negative charges.
Materials:
1 plastic comb
1-piece plastic silk cloth (old/new)
Small bits of paper
Procedure:
1. Rub a plastic comb with a piece of cloth and bring the rubbed end near the bits of paper.
Observe closely.
Q1. What happens when you bring the rubbed comb near the bits of paper?
___________________________________________________________________
Q2. Can you lift the bits of paper with the plastic comb? Why?
___________________________________________________________________
Q3. Explain how the plastic comb attract an uncharged bit of papers.
___________________________________________________________________
___________________________________________________________________
What I Need to Know
At the end of the lesson, you are expected to:
1. Determine the number of protons, number of neutrons and number of electrons in a
particular atom;
2. Name and describe the subatomic particles; and
3. Identify the atomic number and atomic mass.
2
What’s New
Activity 3: The Protons, Neutrons and Electrons
Objective: After doing this activity, you should be able to determine the number of protons,
number of neutrons and number of electrons in a particular atom.
Element
Carbon
Aluminum
Chlorine
Atomic
Number
6
13
17
Atomic
mass
Number of
protons
Number of
neutrons
Number of
electrons
12
27
35
Q1.
Given the atomic number, how would you know the number of protons?
___________________________________________________________________
Q2.
Given the atomic number, how would you know the number of electrons?
___________________________________________________________________
Q3.
Given the atomic number and mass number, how would you know the number of
neutrons?
___________________________________________________________________
Activity 4: What’s the difference?
Objective: Name and describe the protons, electrons, and neutrons.
Materials: Pencil and Pen
Subatomic
Charge
Mass (grams)
particles(symbol)
Electrons
-1
9.109x10-28
Protons
+1
1.672x10-24
Neutrons
0
1.675x10-24
Table 1. Some properties of the three main subatomic particles
Location in the
atom
Outside nucleus
Nucleus
Nucleus
Procedure:
1. Refer to the masses of the subatomic particles in table 1. Arrange the subatomic
particles in increasing mass.
________________________________________________________________
3
Q1. Which subatomic particles is the lightest? _______________________________
Q2. Which subatomic particles is the heaviest? _____________________________
Q3. Which of the subatomic particles have almost the same mass? ___________
Q4. Compare the charges of the three particles indicated in table1.
___________________________________________________________________
2. Take a look again at the table.
Q5. Which subatomic particles makes up most of the mass of the atom?
___________________________________________________________________
Q6. Which particles account for a) the charge of the nucleus and the mass of the
nucleus?
___________________________________________________________________
Activity 5: Complete Me
Directions: Complete the table with the needed information.
Element
1.
2.
3.
4.
5.
Sodium (Na)
Calcium (Ca)
Chromium (Cr)
Silicon (Si)
Sulfur (S)
Atomic Number
Atomic Mass
11
20
24
14
16
23
40
52
28
32
Number of
Neutrons
Guide Questions:
Q1.
Given the atomic number and atomic mass, how would you know the number of
neutrons if you know the mass number and the atomic number?
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
4
What Is It
The Protons, Electrons and Neutrons
An atom is identified by two numbers – the atomic number and the mass number.
A
Zx
(A – Mass Number, Z – Atomic number; x – an element)
Let Atomic number = Z = number of protons = number of electrons
Mass Number A
=
Number of protons + number of neutrons
=
atomic number Z + Number of neutrons
Number of neutrons = Mass number minus atomic number
In an element X, the atomic number Z is placed at lower left and the mass number A
at the upper right. This may be shown in symbol.
ZX
A
How to solve for the number of protons, number of electrons and number of neutrons in
a particular atom.
Example 1.
How many protons(p+), electrons (e-), and neutrons (n0) in (Sodium) 11Na23 atom.
Given:
Element:
Sodium (Na)
Atomic Number of Na =
11
Mass Number of Na =
23
Answer:
p+ = 11; e- = 11; n0 = 12
The symbol 11Na23 designates an atom of sodium that has a mass number of 23
and an atomic number of 11.The number of protons in an atom of sodium is 11(atomic
number z), the number of electrons is also equal to 11 ( number of electron is equal to the
number of protons for a neutral atom). The number of neutrons in the nucleus is equal to 12,
(A –Z). (23 minus 11)
5
.
Example 2.
In an atom of Copper 29Cu64, A = 64 (Mass number) and Z=29 (atomic number)
Atomic number
= 29
Mass number
= 64
Therefore:
Number of p+ = 29
e- = 29
n0 = 35
What’s More
Activity 6: The PEN
Objectives: At the end of the lesson, you should be able to determine the number of protons,
electrons, and neutrons (PEN).
From the given examples above, determine the following:
1. What is the number of protons and number of electrons in Krypton atom? 36Kr84
2. What is the atomic mass of an element with 40 protons,40 electrons, and 46
neutrons?
3. Determine the atomic number, mass number, when the number of protons is 8, n
number of electrons is 8 and number of neutrons is 8.
4. How will you compute for the number of electrons in a potassium with 24 protons and
atomic number of 24?
5. Solve for the atomic mass of an element with atomic number is 30 and number of
neutrons is 35, and number of electrons is 30.
6
Activity 7 – Atomic Structure
Objectives: Determine the number of protons, number of neutrons and number of electrons
in an atom.
Materials: Paper and Pen
Directions: Fill in the table with the needed information.
Element
1.Magnesium (Mg)
2.Cesium (Cs)
3.Iron (Fe)
4.Nickel (Ni)
5.Gold (Au)
6.Cobalt (Co)
7.Bromine (Br)
8.Krypton (Kr)
9.Germanium (Ge)
10.Arsenic (As)
Atomic
Number
12
28
79
Atomic
Mass
24
133
56
Number of
Proton
Number of
Electron
Number of
Neutron
55
26
31
197
79
35
73
32
33
27
32
36
48
42
Q1.
What are the similarities among the same element?
___________________________________________________________________
Q2.
What are the differences among the same element?
___________________________________________________________________
Q3.
What are the differences among the different elements?
___________________________________________________________________
7
What I Have Learned
Activity 8: Try Again!
Directions: Indicate the number of protons (P+), number of electrons (e-), number of neutrons
(n0) of the following atoms.
1.
2.
3.
4.
5.
13Al
27
Number of Protons (P+)
Number of Electrons(e-)
Number of Neutrons (n0)
=
=
=
_____
_____
_____
Number of Protons (P+)
Number of Electrons(e-)
Number of Neutrons (n0)
=
=
=
_____
_____
_____
Number of Protons (P+)
Number of Electrons(e-)
Number of Neutrons (n0)
=
=
=
_____
_____
_____
Number of Protons (P+)
Number of Electrons(e-)
Number of Neutrons (n0)
=
=
=
_____
_____
_____
Number of Protons (P+)
Number of Electrons(e-)
Number of Neutrons (n0)
=
=
=
_____
_____
_____
56
26Fe
53
92
I 127
U235
29
14Si
Q1.
If you know the number of protons of an atom, what other particle would you
automatically know the number? And, why?
_________________________________________________________________________
Q2.
How will you compute for the number of neutrons?
_________________________________________________________________________
8
What I Can Do
Activity 9: THIS IS IT!
Direction: Write at least 5 examples of situations in work related activities that you had
experienced which you think the protons (the positive charged particle), electrons (the
negative charged particle), and neutrons (the neutral charged of atom) was applied.
1.
2.
3.
4.
5.
9
Summary
In this module we have learned that:
1. According to Greek philosopher, Democritus, matter is made up of very tiny particles
called atom.
2. Atom composed of proton, neutron, and electron.
3. The proton is positively charged body. It is found in the atom’s nucleus together with
the neutron.
4. A neutron has no electrical charge. A particle of zero electric charge.
5. An electron is a negatively charged body found to be spinning outside the nucleus.
6. The atomic number of an element is equal to the number of protons or number of
electrons of neutral element.
7. Atomic mass number is equal to the sum of the number of protons and neutron of the
atom.
10
Assessment (Post-Test)
Direction: Choose the letter of the best answer. Write the letter only.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Which of the following particles is not found in the nucleus?
A. Proton
C. Electron
B. Neutron
D. Quarks
Which of the following statements is NOT correct?
A. The total mass of the protons and neutrons in an atom accounts for most of
the mass of the atom.
B. Neutrons have a charge equal to that of electrons.
C. The electron is the first subatomic particle discovered.
D. Electrons are negatively charge.
Chromium has a mass number 52 and atomic number of 24. Solve for number of
protons?
A. 24
C. 52
B. 28
D. 76
They were considered the front runners of scientific studies?
A. Egyptians
C. Romans
B. Greeks
D. Americans
How do you put electric charge to an object?
A. By hanging
C. By cutting
B. By biting
D. By rubbing
In a Bismuth atom, the atomic mass 209, Atomic number is 83. How many numbers
of neutrons does it contain?
A. 209
C. 83
B. 126
D. 292
In an atom of zinc, 30Zn65, the respective numbers of protons, neutrons, and
electrons are:
A. 30, 35, 30
C. 30, 65, 35
B. 30, 65, 35
D. 65, 35, 30
What did J.J. Thompson contribute to the development of knowledge concerning
atom?
A. He discovered the proton
C. He discovered the neutron
B. He discovered the electron
D. Her established the existence of a
positive
In a Fluorine atom 9 F19, what is the number neutrons?
A. 29
C. 10
B. 38
D. 9
If an atom has 24 protons and 24 electrons, what is the atomic number of this
element?
A. Zero
C. 48
B. 24
D. 42
11
12
Pre-Test
1. D
2. B
3. A
4. B
5. C
6. A
7. B
8. A
9. C
10. B
Post-Test
1. C
2. B
3. A
4. B
5. D
6. B
7. A
8. B
9. C
10. B
LESSON 1
Activity 1
Q1.- Solid, liquid, gas
Q2. Al = 1, Hg = 1
H=1
Q3.
Solid - Particles are too close from each other.
Liquid - particles are farther from each other
Gas - are very far
Activity 2
Q1. bits paper – attracted
Q2. Yes, comb become negatively charged
Q3. Adding electrons, the plastic become negative
- the paper is positively charge
Activity 4
1.
2.
3.
4.
5.
Electron
Neutron
Protons and Neutron
Proton is Positive; Electron is
Negative; Neutron is Neutral
Neutron and Proton
Activity 6
1.Proton =36
Electron =36
2.86
3.atomic number =8
Mass number =16
Activity 3
1. proton=6
Neutron=6
Electrons =6
2.Al = proton 13
Neutrons=14
Electron = 13
3.protons=17
Neutrons=18
Activity 5
1.
Na= 12
2.
Ca= 20
3.
Cr= 52
4.
Si = 28
5.
S =16
Q1. Get the difference between Mass number and
atomic number/Number of Protons /number of
electrons
4.Electron = 24
5.atomic mass=65
Key to Answers
13
Activity 7
1.
Mg : P=12 ; N=12
2.
Cs : Atomic Number =55;e =55, N=78
3.
Fe : Atomic Number =26;p =26; N=30
4.
Ni : Atomic Mass = 59; P=28;e =28
5.
Au : p=79; e=79
6.
Co : Atomic Number = 27; Atomic Mass = 59; P=27
7.
Br : Atomic Number =35; e=35
8.
Kr : Atomic Number = 36; P=36
9.
Ge : Atomic Number =32; e=32
10.
As : Mass Number=72;P=33;e=33
Q1. Similar in number of Protons, Electrons, and Atomic Number
Q2. The differ in Number of Neutrons
Q3. They differ in number of Protons, Electrons and Neutrons.
Activity 8
1. Al: P = 13; e = 13; N = 14
2. Fe: P = 26; e = 26; N = 30
3. I: P = 53; e = 53; N = 74
4. U: P = 92; e = 92; N = 163
5. Si; P = 14; e = 14; N = 15
Q1. Number of electrons/Number of protons
Because: atomic number=number of protons = number of electrons
Q3. Difference of mass number and Number of electrons
References
Philippines. Department of Education. 2014. Science 8 Learner’s Module. Quezon City:
Author C. Jauco, Orlando A. Oronce, Science and Technology 111 Conforms SEDP,
Philippine Copyright,1994 by Rex Book Store.1994
Eben S. DY,Magdalina ,Department of education, Science and Technology Textbook for
fourth Year, Quezon City, author 2007
Science: Science and Technology for the Future. (DIWA Scholastic Press Inc.),287
Religioso, T., Vengco, L. Integrated Science textbook for 1st year, 2nd ed. (Phoenix
Publishing Inc., 1995.), 106-107
Grade 8 Science Modules. Philippine Public-School Edition. (Tru-Copy Publishing House,
Inc., 2015),191-199
Frontiers in science & Technology III Chemistry (Diwa Scholastic Press Inc.)
Philippine copyright 2002,94- 96
https://en,m.wikipedia.org>wiki
14
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