Year 10 Physics: Nuclear Physics

Year 10 Physics: Nuclear Physics

• Goal: Describe the structure of an atom in terms of subatomic particles, forces, and isotopes.
• Success Criteria:
  • Interpret atomic number and mass of different elements.
  • Contrast electrostatic force and strong nuclear force.
  • Describe the importance of neutron-proton ratios.
• Area of Study 2: Nuclear Physics - Lesson 1:
  • Explain nuclear stability with reference to forces in the nucleus (electrostatic, strong, and weak nuclear forces).
• Key Vocabulary:
  • Proton
  • Neutron
  • Nucleon
  • Isotope
  • Atomic Number
  • Mass Number
  • Electrostatic Repulsion
  • Strong Nuclear Force
• Science Skills (VCE Physics Unit 1-4):
  • Distinguish between opinions and evidence, scientific and non-scientific ideas.
  • Analyse and evaluate physics-related societal issues (social, economic, legal, and political factors).
  • Analyse current scientific understanding, including models and theories to understand how scientific ideas are contestable and reflect currently available evidence.
  • Evaluate data to determine the degree to which the evidence supports the aim of investigation
  • Analyse the relationship between scientific advances and technological advances, considering ethical principles.
  • Discuss advances in scientific discovery, and developments in technology, and ethical considerations in science.
  • Describe the process of scientific understanding, models and theories through review by the scientific community.
  • Describe how values or needs of society can influence scientific research.
• Most Elements Don't Change:
  • Most elements in the world are stable and do not spontaneously change into other elements.
  • Exceptions exist, where rare elements can sometimes transform into other elements, like gold 194 transforming to platinum 194 after 38 hours.
• Atoms:
  • Atoms consist of a tightly packed positively charged center called the nucleus.
  • Particles in the nucleus are collectively known as nucleons.
  • Protons are positively charged, while neutrons are chargeless.
  • Protons and neutrons are much heavier than electrons that orbit the nucleus.
• Atomic Number:
  • The number of protons in the nucleus determines the chemical properties of the atom and uniquely defines it.
  • Scientists name atoms according to the number of protons in their nucleus, known as their atomic number.
  • A substance is determined by its atomic number.
• Isotopes:
  • Not all atoms of the same element have the same number of neutrons.
  • These different forms of the same element are called isotopes.
  • Scientists differentiate isotopes using mass number (the number of nucleons in the nucleus).
• Electrostatic Force & Strong Nuclear Force:
  • Electrostatic repulsion exists between like charges (e.g., protons).
  • Electrostatic forces increase as charges move closer together.
  • In the nucleus, the electrostatic force of repulsion is overcome by the stronger strong nuclear force.
  • The strong nuclear force acts only over very short distances (10-15 m) to hold neutrons and protons together in the nucleus.
• Radioactive Isotopes:
  • Isotopes that contain unstable nuclei are called radioisotopes.
  • Unstable isotopes can emit nuclear radiation to increase stability.
  • The ratio of neutrons to protons is important for nuclear stability.
• Graph:
  • The number of neutrons versus the number of protons is graphed for various isotopes.
  • Stable nuclei are grouped in a band called the band of stability.
  • The ratio of neutrons to protons increases moving away from elements in the belt of stability.
• Review Questions (Example):
  • How many protons exist in a given atom image; What element does it correspond to?
  • Uranium-235 contains 92 protons, estimate the number of neutrons.
  • Draw a Venn Diagram to compare isotopes and radioisotopes.
  • Explain how nucleons are held together in the nucleus. Why are two different elements potentially possible with the same number of nucleons?
  • Compare isotopes and radioisotopes.