Atomic structure

• What does the word "atom" mean?

  Uncuttable
• What is the size of an atom?

  0.1 to 0.5 nanometers
• What are the main components of an atom?

  Protons, neutrons, and electrons
• Where are protons and neutrons located in an atom?

  In the nucleus
• Where are electrons located in an atom?

  In the outer shells
• What is the mass of a proton and a neutron?

  1 unit
• What is the mass of an electron?

  1/1836 of a proton or neutron
• What is the charge of a proton, neutron, and electron?

  Proton: +1, Neutron: 0, Electron: -1
• What are the two numbers on the periodic table?

  Mass number and atomic number
• How do you calculate the number of protons, neutrons, and electrons in an atom?

  Protons = atomic number, Neutrons = mass number - atomic number, Electrons = atomic number
• What is the overall charge of a neutral atom?

  Zero
• What are the two isotopes of carbon described?

  Carbon-12 and Carbon-14
• How do the two carbon isotopes differ?

  They have the same number of protons (6) but different numbers of neutrons
• What are the three main types of radiation?

  Alpha, beta, and gamma
• How do the three types of radiation differ in terms of properties?

  Alpha is large and highly ionizing, beta is an electron and moderately ionizing, gamma is a wave and highly penetrating
• What is the unit used to measure radiation?

  Becquerel
• What is half-life and how can it be determined from a graph?

  Half-life is the time it takes for half the radioactive atoms to decay. It can be determined by finding the time between 100% and 50% activity on a graph.
• Which type of radiation is best suited for cancer treatment and sterilizing materials?

  Gamma radiation
• What are the main sources of background radiation?

  Radon gas, medical procedures, cosmic radiation, and nuclear weapons testing
• Which type of radiation is best suited for testing the thickness of materials?

  Beta radiation
• What are the two main nuclear processes described?

  Nuclear fission and nuclear fusion
• How does nuclear fission work?

  A heavy nucleus is split by a neutron, releasing more neutrons and energy in a chain reaction
• How does nuclear fusion work?

  Light nuclei are combined to form a heavier nucleus, releasing large amounts of energy
• What are the key developments in the model of the atom over time?

  • Ancient Greeks: Atom is "uncuttable"
  • J.J. Thomson: Plum pudding model (positive sphere with negative bits)
  • Rutherford: Positive center (nucleus) with negative charges (electrons) orbiting
  • Bohr: Electrons in specific orbits around the nucleus
  • Modern: Quantum mechanical model with probability distributions of electrons