Electronic structure

• What is the focus of today's video?

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

  They need a full outer shell to be stable
• What happens if an atom has an incomplete outer shell?

  It reacts with another atom
• What is the atomic number of sodium?

  11
• How many protons does sodium have?

  11 protons
• How many electrons does sodium have?

  11 electrons
• How are electrons arranged around the nucleus?

  In shells around the nucleus
• What is the maximum number of electrons the first shell can hold?

  2 electrons
• What is the maximum number of electrons the second shell can hold?

  8 electrons
• How should electrons be added to the shells?

  In top, right, bottom, left positions
• What happens when you run out of electrons while filling shells?

  You stop adding electrons
• How many electrons does sodium have in its outer shell?

  1 electron
• Why is sodium considered unstable?

  It has an incomplete outer shell
• What do most atoms want to do to achieve stability?

  React to form molecules or compounds
• What do noble gases have in terms of electron configuration?

  Completely full outer shells
• Why do noble gases not react with other elements?

  They have full outer shells
• What is the atomic number of argon?

  18
• How many electrons does argon have?

  18 electrons
• How are the electrons arranged in argon?

  2 in the first shell, 8 in the second, 8 in the third
• How can the electron structure be represented numerically?

  As 2, 8, 8
• How should electrons be represented in diagrams?

  As crosses or dots
• What is the atomic number of calcium?

  20
• How many electrons does calcium have?

  20 electrons
• How are the electrons arranged in calcium?

  2 in the first shell, 8 in the second, 8 in the third, 2 in the fourth
• What is the electron structure of calcium?

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

  It has an incomplete outer shell
• What happens if calcium loses two outer electrons?

  It becomes stable with a full outer shell
• What charge does a calcium ion have?

  2 plus positive charge
• How is a calcium ion represented in diagrams?

  With square brackets and charge in the corner
• What is the atomic number of fluorine?

  9
• How many electrons does fluorine have?

  9 electrons
• How are the electrons arranged in fluorine?

  2 in the first shell, 7 in the second
• What does fluorine need to become stable?

  Gain one more electron
• What charge does a fluoride ion have?

  1 minus negative charge
• How is the electron structure of fluoride represented?

  As 2, 8
• What is the process of electron arrangement in atoms?

  • Electrons are arranged in shells around the nucleus.
  • First shell holds 2 electrons.
  • Second shell holds 8 electrons.
  • Third shell holds 8 electrons.
  • Electrons are added in specific positions.
• What are the differences between sodium, calcium, and fluorine in terms of electron stability?

  • Sodium: 1 electron in outer shell, unstable.
  • Calcium: 2 electrons in outer shell, unstable.
  • Fluorine: 7 electrons in outer shell, needs 1 more to be stable.
• What are the characteristics of noble gases?

  • Full outer shells of electrons.
  • Do not react with other elements.
  • Found in group zero of the periodic table.
• How do you determine the electron arrangement of an element?

  1. Find the atomic number.
  2. Draw the nucleus.
  3. Fill the shells according to maximum capacity.
  4. Represent the arrangement numerically or diagrammatically.