ASIAN COLLEGE FOUNDATION
SENIOR HIGH SCHOOL DEPARTMENT
MODULE 2
Physical SCIENCE
Third Quarter
OBJECTIVES:
1. Give evidence for and describe the formation of heavier elements during star formation and evolution
and explain how the concept of atomic number led to the synthesis of new elements in the laboratory.
2. Determine if polar or non-polar molecule and relate the polarity to its properties.
3. Describe intermolecular forces and explain the effect of forces on the properties of substances.
4. Explain how biological molecular structures (carbohydrates,lipids,nucleic acid, and proteins) determine
their properties and functions.
5. Using collision theory, explain the effects of concentration, temperature, and particle size on the rate of
reaction and define catalyst and how it affects reaction rate.
6. Determine the limiting reactant in the reaction and calculate the amount of product formed.
7. Describe how energy is harnessed from different sources: fossil fuel, biogas, geothermal, hydrothermal,
batteries, solar cells, and biomass.
8. Identify the active ingredients of cleaning products used at home and the use of the other ingredients in
cleaning agents.
PHYSICAL SCIENCE
LESSON 1:
Formation of the elements in the universe
DISCUSSION
How were elements heavier 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.
Evolution of Stars
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.
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.
The atomic nucleus
Matter is made up of atoms. An atom is compose of negatively charged particles, called electrons,
which surround a positively charged nucleus. The nucleus is the central core of an atom. It consists of
positively charged protons and electrically neutral neutrons. The charged on the electron is designated
negative(-) and that on the proton positive (+).
The particles in an atom are designated by certain numbers. The atomic number, symbolized by
the letter Z, is the number of protons in the nucleus of each atom of that element. An element is a
substance in which all the atoms have the same number of protons (the same atomic number, Z).
Electrons may gained or lost by an atom, and the resulting particle called an ion, will be electrically
charged. For instance, a sodium atom (Na) loses an electron, then it becomes a sodium ion (Na+). The
sodium ion still has the same atomic number of protons (11).
The neutron number (N) is the number of neutrons in a nucleus. And the mass number (A) is the
number of protons plus neutrons in the nucleus: the total number of nucleons.
N - neutrons
Or
(AXZ)
The number of neutrons (N) in a nucleus is easily determined by subtracting the atomic number
(Z) from the mass number (A). Where : N = A - Z
EXAMPLE
Determine the number of protons, electrons and neutrons in the fluorine atom.
19
F9
Atomic number Z is 9, so the number of protons is 9 (as is the number of electron for a neutral atom). The
mass number A is 19, so the number of neutrons is N = A - Z = 19 - 9 = 10. The answer is 9 protons, 9
electrons, and 10 neutrons.
ACTIVITY 1
Find and trace down WORDS of cosmologies from different religions and cultures based on theirbeliefs.
Use LINE to trace your answer.
Y
T
I
N
A
I
T
S
I
R
H
C
U
V
M
A
M
D
F
S
M
Z
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K
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F
S
N
B
F
G
D
X
N
U
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B
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B
L
E
D
H
F
C
J
Q
U
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D
N
L
P
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A
M
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I
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J
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A
B
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K
E
Y
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L
P
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Z
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Q
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O
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M
Example:
Christianity
ACTIVITY 2
Refer your answer from above.
1. How will you define cosmology?
2. Do you think is there a proof where cosmologies from different religions and culture came from?
3. Why different cultures have the need to explain where they came from and how the world was
created.
4. Is a science a theory or a scientific evidence? Explain.
ACTIVITY 3.
Fill in the gaps in this table.
Element symbol
Ga
Protons
Neutrons
B
15
39
20
Electrons
Mass number
9
10
17
31
11
Your solution here:
GUIDE QUESTIONS/ GENERALIZATION:
1. How heavier elements formed?
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2. When does evolution of star begin?
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3. What pieces of evidence support the star formation theory?
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4. What makes a nucleus?
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ASSESSMENT/REFLECTION
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FEEDBACK
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ADDITIONAL RESOURCES
INTERNET
https://www.slideshare.net/JeromeJerome1/formation-of-light-and-heavy-elements?from_action=save
https://physicstoday.scitation.org/doi/full/10.1063/PT.3.3815
https://www.facebook.com/notes/grade-11-physical-science-vnhs/lesson-12-the-formation-of-heavierelements-during-star-formation-and-evolution/1880966238586259/
https://www.slideshare.net/JhayGonzales/synthesis-of-the-new-elements-in-the-laboratory
https://www.quora.com/How-does-the-idea-of-an-atomic-number-lead-to-synthesizing-new-elements
https://www.discovermagazine.com/planet-earth/how-can-scientists-create-new-elements
BOOK
REX BOOK STORE, An Introduction to Physical Science, 14th Edition, by James T. Shipman, et., al