Atomic structure, Isotopes & Electrons shells

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

  A quick review of everything about the atom from chemistry
• What are the two main components of an atom discussed in the video?

  The nucleus and electrons
• What particles are found in the nucleus of an atom?

  Protons and neutrons
• What is the charge of protons and neutrons?

  Protons are positively charged, while neutrons are 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?

  Electrons are about two thousand times smaller
• What is the charge of electrons?

  Electrons have a negative charge of one
• 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?

  It determines which element an atom is
• What is the mass number of lithium?

  7
• How is the mass number calculated?

  By adding the number of protons and neutrons together
• How many protons and neutrons does lithium have?

  Three protons and four neutrons
• How can you determine the number of electrons in an atom?

  The number of protons and electrons is the same
• What are isotopes?

  Atoms with the same number of protons but different numbers of neutrons
• What is an example of isotopes of lithium?

  Lithium-6, Lithium-7, and Lithium-8
• What is the stability of isotopes?

  Generally, only one or two of an element's isotopes are stable
• What happens to unstable isotopes?

  They tend to decay into other elements by emitting radiation
• What is the process called when unstable isotopes decay?

  Radioactive decay
• What do electrons in an atom do?

  They are arranged in energy levels or shells
• How do electrons move between energy levels?

  They can jump to a higher energy level if they gain enough energy
• What causes an electron to become excited?

  Gaining enough energy from electromagnetic radiation
• What happens after an electron becomes excited?

  It will fall back down to a lower energy level and re-emit energy
• What is ionization?

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

  It becomes a positive ion
• What does the term ionizing radiation mean?

  Radiation that can knock electrons off atoms
• What should you do if you enjoyed the video?

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