Electron Configuration

• What is an atomic orbital?


  A region around a nucleus for electrons
• How many electrons can an atomic orbital hold?

  Up to two electrons
• What are the types of orbitals mentioned?

  s, p, d, and f orbitals
• What is a subshell?

  All orbitals of the same type in a shell
• What happens to the energy of subshells as you move away from the nucleus?

  Energy increases
• What are the three rules for filling atomic orbitals?

  1. Fill lowest energy orbitals first
  2. Up to two electrons per orbital with opposite spins
  3. Fill individual orbitals before pairing in same energy level
• How do you represent an electron's spin in diagrams?

  Using an arrow
• What is the electron configuration of hydrogen?

  1s$^1$
• How many electrons does helium have?

  Two electrons
• What is the electron configuration of helium?

  1s$^2$
• How many electrons does lithium have?

  Three electrons
• What is the electron configuration of lithium?

  1s$^2$ 2s$^1$
• How many electrons does nitrogen have?

  Seven electrons
• What is the electron configuration of nitrogen?

  1s$^2$ 2s$^2$ 2p$^3$
• What does the electron configuration show?

  Sub shells, not individual orbitals
• What will be covered in the next video?

  • More complicated examples of orbital filling
  • Two elements that are exceptions to the rules
  • Explanation of why these exceptions occur