atomic structure

• What is the main topic of today's video?

  A quick review of everything about the atom from chemistry
• What does the nucleus of an atom contain?

  Protons and neutrons
• What is the charge of protons?

  Positive charge (+1)
• What is the charge of neutrons?

  Neutral
• What is the relative mass of protons and neutrons?

  Both have a relative mass of one
• How much smaller are electrons compared to protons or neutrons?

  About two thousand times smaller
• What is the charge of electrons?

  Negative charge (-1)
• What does each box in the periodic table represent?

  A particular element
• What is the elemental symbol for lithium?

  Li
• What does the atomic number represent?

  The number of protons in the atoms of that element
• Why is the atomic number important for identifying an element?

  It determines which element it is
• What does the mass number indicate?

  The total number of protons and neutrons together
• What is the mass number of lithium?

  7
• How many electrons does lithium have?

  3 electrons
• How many protons does lithium have?

  3 protons
• What are isotopes?

  Atoms with the same number of protons but different numbers of neutrons
• What are the isotopes of lithium mentioned?

  Lithium-6, Lithium-7, and Lithium-8
• How many neutrons does lithium-6 have?

  3 neutrons
• How many neutrons does lithium-8 have?

  5 neutrons
• What is radioactive decay?

  The process by which unstable isotopes decay into other elements by emitting radiation
• What types of radiation can unstable isotopes emit?

  Alpha, beta, or gamma radiation
• What are the energy levels in an atom called?

  Shells
• How do electrons move between energy levels?

  They can jump to a higher energy level if they gain enough energy
• What happens when an electron becomes excited?

  It jumps to a higher energy level
• What provides the energy for an electron to jump to a higher energy level?

  Electromagnetic radiation
• What happens after an electron falls back to a lower energy level?

  It re-emits the energy as electromagnetic radiation
• What is ionization?

  When an outermost electron absorbs enough energy to completely leave the atom
• What charge does an atom have after ionization?

  A positive charge
• What does the term ionizing radiation mean?

  Radiation that can knock electrons off atoms
• What are the key components of an atom?

  • Nucleus: contains protons and neutrons
  • Protons: positively charged (+1), relative mass of one
  • Neutrons: neutral, relative mass of one
  • Electrons: negatively charged (-1), about 2000 times smaller than protons/neutrons
• What information is contained in a periodic table box?

  • Elemental symbol (e.g., Li for lithium)
  • Atomic number (number of protons)
  • Mass number (total number of protons and neutrons)
• What is the relationship between protons and electrons in an atom?

  • The number of protons equals the number of electrons in a neutral atom.
• What are the characteristics of isotopes?

  • Same number of protons (same atomic number)
  • Different numbers of neutrons (different mass numbers)
  • Generally, only one or two isotopes are stable
• What happens during radioactive decay?

  • Unstable isotopes emit radiation (alpha, beta, gamma)
  • Can decay into other elements
• How do electrons behave in an atom?

  • Arranged in energy levels (shells)
  • Can jump to higher energy levels when gaining energy
  • Re-emit energy as electromagnetic radiation when falling back
• What is the significance of ionization in atoms?

  • An outermost electron can leave the atom, creating a positive ion
  • Ionizing radiation can knock electrons off atoms