Formation of Heavy Elements (Part I)

1. Formation
of Heavy
Elements
(Part I)

2. Give evidence for and
describe the formation of
heavier elements during
star formation and
evolution. (S11/12PS-IIIb-11)

3. Collision - The sudden, forceful coming together in
direct contact of two bodies.
Combination - is a type of reaction in which two or
more elements or compounds (reactants) combine to
form a single compound (product).
Isotopes - Atoms with the same number of protons but
different numbers of neutrons are called isotopes.

6. Direction: Read each statement below carefully.
Place a T on the line if you think a statement is
TRUE. Place an F on the line if you think the
statement is FALSE. If you have questions, raise
your hand and ask your teacher.

7. 1. Elements are made up of
subatomic particles called
protons, neutrons and
electrons.

8. 2. The identity of an element
depends on how many
neutrons it has.

9. 3. Lithium is one of the
elements formed during the
big bang nucleosynthesis.

10. 4. Nucleosynthesis combines
nucleons (protons and
neutrons) to form new
elements.

11. 5. The big bang is an explosion.

12. 6. The universe was colder 13.8
billion years ago.

13. 7. The higher the energy of the
particles in an object are the
higher the temperature of that
object will be.

14. 8. Mass can be converted into
energy.

15. Let’s Check!

16. 1. Elements are made up of
subatomic particles called
protons neutrons and
electrons.

18. 2. The identity of an element
depends on how many
neutrons it has.

21. 2. The identity of an element
depends on how many
neutrons it has.

22. 3. Lithium is one of the
elements formed during the
big bang nucleosynthesis.

23. 3. Lithium is one of the
elements formed during the
big bang nucleosynthesis.

24. 4. Nucleosynthesis combines
nucleons (protons and
neutrons) to form new
elements.

25. Nucleosynthesis
Nucleo - nucleus
Synthesis - Creating something
new by combining separate
materials.

26. 5. The big bang is an explosion.

27. Contrary to popular belief the
big bang is not an explosion.
The word explosion is
misleading that is why we
prefer to use the word
expansion to refer to big bang.

28. According to the big bang theory the
universe was extremely small even
smaller than an atom. It was also
extremely dense and extremely hot,
but 13.8 billion years ago it began to
expand, and the formation of most
light elements occurred just a few
seconds after the big bang.

30. 6. The universe was colder 13.8
billion years ago.

31. The universe was very hot billions of
years ago. However, it cooled down as
it expanded. This fact is important in
our study of element formation. It tells
us that there was a time when the
universe was hot enough to form
elements and then it stopped because
it cooled down.

32. 7. The higher the energy of the
particles in an object are the
higher the temperature of that
object will be.

33. Temperature is a measure of the
average kinetic energy of the
particles in an object. The higher
the energy of these particles are
the higher the temperature of
the object will be.

35. If you are too shy to tell
your friends that you are
hot maybe you can tell
them that the particles
inside, you have a lot of
energy.
Joke Time!

36. The temperature of the
universe can also tell us
whether it's possible for
new elements to be
created there.

37. When it's too hot the
particles have too much
energy they just get
destroyed when they
collide.

38. If the particles lack energy,
they will just bounce upon
collision. No new element
made.

39. However, if the temperature
of the universe is just right
protons and neutrons can
combine when they collide.
When that happens, new
elements are made.

40. 8. Mass can be converted into
energy.

42. It is important for us to
understand and to know
that it is possible for mass
to be converted into
energy.

43. Later you will see that when
elements are made energy
is released. Now, where
does this energy come
from? It comes from mass.

44. How did you do?

45. Formation of
Heavy
Elements
(Part I)

46. Did you know that protons
and neutrons formed a few
seconds after the big bang.

47. At first the universe was so
hot, and the particles were
so energetic that when
they collided, they just got
destroyed.

48. However, the universe is expanding
and as the universe expands it
cools. For a few minutes after the
big bang the temperature of the
universe reached the point where
the protons and neutrons could
combine when they collided.

49. Through this process new
elements were made, and
we call this the Big bang
nucleosynthesis

50. How does this big bang
nucleosynthesis work?

51. Protons and neutrons collide
and combine to form to
deuteron. Deuteron is an
isotope of hydrogen that has
one proton and one neutron.

53. How do we know that this
deuteron is an isotope of
hydrogen and not of any other
elements? It's because it has
one proton and all atoms that
have one proton is hydrogen.

54. Soon another neutron
collides and combines with
it to form triton.

56. Again, this is an isotope of
hydrogen because it has
one proton. Then again,
another proton collides and
combines with it to form
Helium. We know that this
is helium because it has
two protons.

58. Most of what were formed were
hydrogen and helium. However,
some lithium and beryllium were
also formed. One way lithium was
formed was through the collision
and combination of helium-4 and
triton.

60. One way Beryllium was
formed was through the
collision and combination
of helium-4 and helium-3.

62. As the universe continued to expand the
temperature dropped to a point where the
particles no longer had enough energy to
combine. When they collide, they just
bounced. The universe was able to create a
lot of hydrogen and helium and a few
lithium and beryllium that is the process of
Big bang nucleosynthesis.

63. As you can see it is very
straightforward and very
easy to understand. All you
must remember are the
words collision and
combination.

64. How are the elements heavier
than beryllium formed?

65. So far, we've learned that
we need enough heat so
that the particles have
enough energy to combine
when they collide.

66. However, we know that the
universe can no longer provide
that heat because like what we
learned earlier as the universe
expands it cools.

67. Now can you think of a hot
place where heavier
elements could possibly
form?

69. Twinkle, twinkle big, big star.
Now I know how hot you are.
Heavy elements exist because of
you.
Gold, calcium, oxygen and silver
too.

70. Stars don't just twinkle they do
more than that. They make it
possible for elements to form. It
also tells us that stars are not little
they're big and they only look
small because they're very far
away.

71. Lastly the rhyme tells us
that stars are so hot they
can provide energy for
another type of
nucleosynthesis the Stellar
nucleosynthesis.

72. When elements are formed
inside a star, we call that
Stellar nucleosynthesis.

73. It all starts with a stellar nebula.
The Stellar nebula is the
birthplace of the star. It is called
such because it is where the
stars are born. It is a huge
clump of gas and dust particles.

75. Eventually gravity will collapse this
structure and as it collapses, the force
of gravity increases the kinetic energy
of the particles. Hydrogen atoms gain
enough energy to collide and combine
to form helium atoms through the
process called Nuclear fusion.

76. In a nutshell nuclear fusion
happens when atoms gain
enough energy to combine
when they collide. This process
releases huge amount of
energy.

78. When four hydrogen atoms
combine to form helium,
some of the mass of
hydrogen is converted into
huge amount of energy.

79. This energy blows the contents of the
star out but instead of being ejected,
the contents of the star are held in
place by gravity. When the star is at
this stage, we say that it is in its Main
sequence stage.

80. Now what happens inside the star
in its main sequence stage
depends on how big it is. In other
words, different types of nuclear
fusion happens inside the star
depending on how big it is.

81. For medium-sized stars like
our sun the proton-proton
chain reaction is
dominant.

82. For more massive stars the
CNO or carbon nitrogen
oxygen cycle is more
dominant.

83. The proton-proton chain reaction
starts with two protons or two
hydrogen atoms colliding and
combining. As they combine one of the
protons turns into a neutron because
of this, a positron and a neutrino are
released the positron will annihilate
with an electron and release energy.

85. Protons can turn into a
neutron and neutron can
turn into a proton. Now
what we have left is a
deuteron which is an
isotope of hydrogen.

86. Later another proton hits deuteron
and helium-3 is formed. When this
helium-3 emits another helium-3
which was formed from the collision
and combination of other hydrogen
atoms they collide, and they
combine.

87. Two protons will be released
to perform another nuclear
reaction and that is how
helium is formed through the
process of proton proton
chain reaction.

88. That is how the light elements
were formed during the big
bang nucleosynthesis and
how some light elements
were formed during the
stellar nucleosynthesis.

89. Eight important concepts
that will help us
understand how elements
were formed.

90. 1. All atoms are made up
of subatomic particles
called protons neutrons
and electrons.

91. 2. The identity of an element
depends on how many protons
it has just look at the total
number of protons that an
atom has and you will know
what type of element it is.

92. 3. The light elements
hydrogen helium lithium
and beryllium were the
very first atoms to form.

93. 4. Nucleosynthesis combines
nucleons to form new
elements to form a new
element all you really have to
do is to collide particles and
combine them.

94. 5. Big bang is not an
explosion it is the
expansion of space.

95. 6. As the universe expands it
cools this tells us that the
universe was hot before. Hot
enough to energize particles to
combine and collide, but as the
time went by it became cooler
and cooler.

96. 7. The higher the energy of
the particles in an object
are the higher the
temperature of that object
will be.

97. 8. Mass can be converted
into energy.

98. 8. Mass can be converted
into energy.

99. we also learned that a few moments
after the big bang, protons and
neutrons were formed. For a few
minutes the universe was hot enough
to make the combination of these
subatomic particles possible and
because of that helium lithium and
some beryllium were formed.

100. However, when the
universe was no longer hot
enough, the
nucleosynthesis stopped.
The story of the elements
did not end there though.

101. Stars were born and
nuclear fusion occurred at
their core inside hydrogen
atoms combine to form
helium and release energy.

102. Many people may express doubt in
your ability to learn. You can choose to
be like the moon that always depends
on others to shine but you can also
choose to be a star that shines
whether or not there is light around.

103. What is the importance of the
formation of light elements?
What do you think will happen if the
formation of the elements during the
Big Bang and during stellar evolution
did not occur?

104. Direction: Choose
the letter of the
correct answer.

105. 1. Which of the following is not
considered as light element?
A. Helium
B. Hydrogen
C. Lithium
D. Iron

106. 2. Which of the following is true about
nucleosynthesis?
A. It is the division of atomic particle.
B. The combination of elements to form
compound.
C. It is the creation of everything including all
matter in universe.
D. It is the process of creating new atomic
nuclei from pre-existing nuclei.

107. 3. At which phase of star life
cycle is our sun in?
A.main sequence star
B.planetary nebula
C.red giant
D. white dwarf

108. 4. How is the energy of the star
produced?
A.by combustion
B.by decomposition
C.by nuclear fission
D. by nuclear fusion

109. 5. Which type of nuclear fusion
occurs at the core of a medium-sized
star?
A. alpha leather process
B.CNO cycle
C. Proton-proton chain reaction
D. tri-alpha process

110. 1. Draw your own understanding of
the formation of of the elements
during the Big Bang and during
stellar evolution.
2. How heavier elements are formed?