1.8 Electronic Structure

• What is the main topic discussed in the video?

  The arrangement of electrons in atoms
• Why do most atoms, like fluorine, have an incomplete outer shell of electrons?

  Because they need a full outer shell to be stable
• What is the atomic number of sodium?

  11
• What happens when atoms do not have a full outer shell?

  They will react with another atom to gain or lose electrons
• How many protons and electrons does sodium have?

  Sodium has 11 protons and 11 electrons
• How are electrons arranged around the nucleus of an atom?

  Electrons are arranged in shells around the nucleus
• How many electrons can the first shell hold?

  The first shell can hold 2 electrons
• How many electrons can the second shell hold?

  The second shell can hold up to 8 electrons
• What is the best way to add electrons to the shells?

  Put a single electron in the top, right, bottom, and left positions before pairing
• What does it mean if an atom is unstable?

  It means the atom wants to react with another atom to have a full outer shell
• What are noble gases known for regarding their electron configuration?

  Noble gases have completely full outer shells
• Why do noble gases not react with other elements?

  Because they have full outer shells and do not need to gain or lose electrons
• How would you find the electron arrangement of argon?

  By noting that argon has an atomic number of 18, indicating 18 electrons
• What is the electron structure of argon?

  2, 8, 8
• How many electrons are in the first shell of argon?

  2 electrons
• How many electrons are in the second shell of argon?

  8 electrons
• How many electrons are in the third shell of argon?

  8 electrons
• What is the atomic number of calcium?

  20
• What is the electron arrangement of calcium?

  2, 8, 8, 2
• Why is calcium considered unstable?

  Because it has only 2 electrons in its outer shell instead of 8
• What happens to calcium when it loses two outer electrons?

  It becomes a calcium ion with a 2+ charge
• How do we denote ions in diagrams?

  By drawing big square brackets around them and writing the overall charge in the top right corner
• What is the electron structure of a fluoride ion?

  2, 8
• Why does fluorine need to gain one more electron?

  To have a full outer shell and become stable
• What charge does a fluoride ion have?

  A charge of -1
• What is the process of determining the electron arrangement for the first 20 elements in the periodic table?

  1. Identify the atomic number.
  2. Determine the number of electrons.
  3. Fill the first shell with 2 electrons.
  4. Fill the second shell with up to 8 electrons.
  5. Fill the third shell with up to 8 electrons.
  6. Write the electron structure in the format of numbers.
• What are the key points about electron arrangements in atoms?

  • Atoms need a full outer shell to be stable.
  • Electrons are arranged in shells around the nucleus.
  • The first shell holds 2 electrons, the second holds 8, and the third holds 8.
  • Atoms may gain or lose electrons to achieve stability.