Physical science reviewer

• Atoms are the smallest unit of matter and the basic unit of matter
• Matter is anything that occupies space and has mass
• Mass is the amount of atoms present in matter
• Weight is the amount of atoms present in matter plus the effect of gravity
• Atoms are made up of sub-atomic particles:

  • Protons have a positive charge
  • Neutrons have no charge
  • Electrons have a negative charge
• Atoms are not visible to the naked eye, only visible when using a Scanning Tunneling Microscope (STM)
• The Big Bang theory is the most acceptable theory on how the universe was formed
• The universe is continuously inflating and expanding according to the Big Bang theory
• Elements are formed during the 3 stages of Nucleosynthesis:

  1. Big Bang

  2. Stellar Formation/Evolution (Birth of the star)

  3. Stellar explosion (Supernova) (Death of the star)
• During the Big Bang, 3 elements are formed:

  • Hydrogen (H)
  • Helium (He)
  • Lithium (Li)
• During Stellar Formation, Be-Fe elements are formed (23 elements)
• During Stellar Explosion, elements heavier than iron (Fe) are formed
• Atomic number and the number of protons identify the atom
• Quark is the fundamental unit of protons, neutrons, and electrons
• The universe expands and cools down, leading to the formation of elements
• 75% of the elements in the universe are hydrogen and 25% are helium
• Ions are charged atoms
• Cations are positively charged ions
• Anions are negatively charged ions
• When the number of protons is greater than electrons, it is called a cation
• When the number of electrons is greater than protons, it is called an anion
• A neutral atom has an equal number of protons and electrons
• Nucleosynthesis is the process of creating nuclei by combining protons and neutrons
• Isotopes are atoms that have the same number of protons but differ in the number of neutrons
• Protium is an isotope with one proton and no neutrons
• Deuteron is an isotope with one proton and one neutron
• Triton is an isotope with one proton and two neutrons
• Nuclear reactions involve nuclei combining with another nucleus or splitting into smaller particles
• Fusion occurs when nuclei combine with another nucleus
• Fission occurs when a nucleus splits into smaller particles
• Nuclear reactions involve radioactivity, which refers to the emission of radioactive particles during the reaction
• redshift is an increase in the wavelength, and corresponding decrease in the frequency and
• Edward hubble is the proponent of the red shift theory