Quarter 1: Week 1
Exploring the Formation of
Elements During Stellar Formation
and Evolution
ATTHEENDOFTHESESSION, THELEARNERS
SHOULDBEABLETO:
Give evidence for and describe the formation of
heavier elements during star formation and
evolution.
Explain how the concept of atomic number led to
the synthesis of new elements in the laboratory.
A. Big Bang Theory
1.
WHICH OF THE
FOLLOWING IS THE
MOST ACCEPTED
THEORY ABOUT THE
FORMATION OF THE
UNIVERSE THAT
EXPLAINS WHY IT
CONTINUES TO
EXPAND?
B. Divine Creation Theory
C. Steady State Theory
D. Oscillating Theory
The Big Bang theory is an effort to
explain what happened at the very
beginning of our universe. Our universe
sprang into existence as "singularity"
around 13.7 billion years ago.
2. ARRANGE THE
FOLLOWING EVENTS TO
FORM THE RIGHT
SEQUENCES OF THE
EVENTS OF THE
BIG BANG THEORY.
According to the Big Bang Theory,
the temperatures in the early
universe were so high that fusion
reactions could take place.
This resulted in the formation of
light elements: hydrogen,
deuterium, tritium , helium (two
isotopes), lithium and trace
amounts of beryllium.
Definition of Terms:
Atom - is the smallest unit of ordinary matter that forms a
chemical element. Every solid, liquid, gas, and plasma is
composed of neutral or ionized atoms.
Isotopes - Each of two or more forms of the same element that
contain equal numbers of protons but different numbers of
neutrons in their nuclei, and hence differ in relative atomic mass
but not in chemical properties; in particular, a radioactive form
of an element.
Definition of Terms:
Atomic number is usually the number of protons present in an
element’s nucleus. It is also the value found associated with an
element on the periodic table because it is the key to the
element's identity.
Atomic mass is associated with the number of neutrons and
protons that are present in a particular nucleus of an element.
The word “stellar” means star and the
formation of elements in the center of
the star is called stellar nucleosynthesis.
During this Stellar evolution, nuclear
reactions continued, which produced
elements heavier than lithium/beryllium
to iron.
Produced elements
Produced elements
from Hydrogen to
heavier than
Beryllium.
Beryllium to Iron.
Produced elements
Produced elements
such as Beryllium,
such as Neon , Silicon
Carbon up to
up to Iron.
Oxygen.
The star can keep growing into
supergiant as it accumulates m
Apha fusion processes continue
the core via the alpha ladder. M
and more alpha particles are fu
to create heavier elements all t
way to iron, making the core a
star itself more massive.
The star can keep growing into
supergiant as it accumulates m
Apha fusion processes continue
the core via the alpha ladder. M
and more alpha particles are fu
to create heavier elements all t
way to iron, making the core a
star itself more massive.
The star can keep growing into
supergiant as it accumulates m
Apha fusion processes continue
the core via the alpha ladder. M
and more alpha particles are fu
to create heavier elements all t
way to iron, making the core a
star itself more massive.
Radio active decay is the process
by which an unstable atomic
nucleus loses energy by radiation.
A material containing unstable
nuclei is considered radioactive.
Three of the most common types
of decay:
1.alpha decay (훼-decay)
2. beta decay (훽-decay)
3. gamma decay (훾-decay)
Alpha Decay:
two protons and two neutrons are immitted resulting to a lighter new element.
Beta Decay:
a neutron becomes a proton and an electron will be ejected resulting to a new
element with the same mass.
Gamma Decay:
gamma ray will be emitted when a radioactive nuclide leaves a nucleus in an
excited state.
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
The atomic number is the number
of protons (positively charged
particles) in an atom.
In 1919, Ernest Rutherford
successfully carried out a nuclear
transmutation reaction a process
of transforming one element or
isotope into another element.
James Chadwick discovered the
neutron in 1932, as a previously
unknown neutral particle produced
along with 12C by the nuclear reaction
between 9Be and 4He:
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.
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.