Electron Configuration

• What should you be able to do by the end of the video?

  Work out electron configuration of elements
• 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 is the first rule for filling orbitals?

  Fill lowest energy orbitals first
• How many electrons can occupy the same orbital?

  Two electrons with opposite spins
• What is the third rule for filling orbitals with the same energy?

  Put electrons in individual orbitals first
• How do you represent an electron's spin?

  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?

  Only the subshells, not individual orbitals
• 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. Electrons in same energy orbitals occupy individual orbitals first
• What is the process for determining the electron configuration of an element?

  1. Identify the number of electrons
  2. Fill the lowest energy orbitals first
  3. Follow the three rules for orbital filling
  4. Write the electron configuration notation
• What are the exceptions to the rules for filling orbitals?

  • Some elements have irregular electron configurations
  • These exceptions occur due to stability considerations
• What is the focus of the second video in the series?

  Working out electron configuration of atoms
• What do different atomic orbitals have?

  Different energies
• What are the three rules for placing electrons in orbitals?

  1. Fill lowest energy orbitals first
  2. Up to two electrons per orbital with opposite spins
  3. Electrons occupy individual orbitals before pairing in same energy level
• How many electrons does oxygen have?

  Eight electrons
• What is the electron configuration of oxygen?

  1s2 2s2 2p4
• What does the electron configuration show?

  Sub shells, not individual orbitals
• How many orbitals does the d subshell contain?

  Five orbitals
• Which sub shell is filled before the 3d subshell?

  4s sub shell
• How many electrons does iron have?

  26 electrons
• What is the electron configuration of iron?

  1. 1s2
  2. 2s2
  3. 2p6
  4. 3s2
  5. 3p6
  6. 3d6
  7. 4s2
• In what order is the electron configuration written?

  Order of electron shells
• How many electrons does vanadium have?

  23 electrons
• What is the electron configuration of vanadium?

  1. 1s2
  2. 2s2
  3. 2p6
  4. 3s2
  5. 3p6
  6. 3d3
  7. 4s2
• What are the exceptions to the electron configuration rules?

  Chromium and copper
• How many electrons does chromium have?

  24 electrons
• How many electrons does copper have?

  29 electrons
• What is the actual electron configuration of chromium?

  • 1s2
  • 2s2
  • 2p6
  • 3s2
  • 3p6
  • 3d5
  • 4s1
• What is the actual electron configuration of copper?

  • 1s2
  • 2s2
  • 2p6
  • 3s2
  • 3p6
  • 3d10
  • 4s1
• Why is the 3d subshell more stable when half or completely full?

  It minimizes electron repulsion