Physical Science

1. Formation of Elements in the
Big Bang and Stellar
Evolution
MODULE 1

2. Objectives:
▪ Explain and give evidence for the formation of light elements in
the big bang theory.
▪ Describe and give evidence for the formation of heavier
elements during star formation and evolution; and
▪ Write the nuclear fusion reactions in stars, which led to the
formation of new elements.

3. Big bang nucleosynthesis
▪ As the universe cooled down and the subatomic particles formed, it
entered the phase called big bang nucleosynthesis.

4. The process that
creates a new
atomic nucleus
from pre-existing
nucleons, primarily
protons (+) and
neutrons.

5. Big bang Nucleosynthesis
Proton + neutron= Deuterium
Deuterium+ neutron=Tritium
Big bang Nucleosynthesis strongly
favors the very light isotopes like
Hydrogen (1.008) and Helium (4.003)
because they are dense less rather
than other elements with larger
atomic mass.

6. Atom is the smallest unit of matter.
Sub-atomic particles:
Proton (+)Positively charge particle
Neutron No charge particle
Electron (-)Negatively charge particle

7. Nuclear fusion
▪ The process by which light nuclei fuse together to form a
heavier nucleus.
Isotope- is a form of an element that has
the same atomic number as that of the
original element but with a different
atomic mass or mass number.
Isotopes produced during the big bang
nucleosynthesis were H-1, H-2, He-3, He-4, and Li-7
Fusion- combination or to fuse together
Fission- separation or splitting of particles.

9. Stellar nucleosynthesis
▪ The formation of heavy elements by the fusion of
lighter nuclei in the interior of stars.

10. Stars are hot and dense enough to burn
hydrogen -1 (1H) to Helium -4 (4He).
▪ There are many nuclear synthetic
pathways or nuclear fusions to produce
heavy elements:
▪ Carbon-Nitrogen-oxygen cycle
▪ Proton-proton fusion
▪ Triple alpha process
Layers near core of stars
have very high temperatures
enough to nucleosynthesize
heavy elements such as
silicon and iron.

13. Supernova
▪ It is an explosive death of a star.

14. Add a Slide Title - 1

15. Add a Slide Title - 3

16. Activities are on the next slide.
Thank you!

17. MODULE 1: Formation of Elements in the Big Bang and Stella Evolution
Activities
What Have I Learned So Far?
Page 5
What Have I Learned So Far?
Pages 7-8
Answer the following activities below using your textbook.Write it
on a long bond paper. Don’t forget to write your name, module # &
title, Activity and page.

18. Add a Slide Title - 5