Electron configuration

• What is the atomic number of Nitrogen?

  7
• What does the mass number represent?

  It is the total number of protons and neutrons
• What sublevels are present in the first energy level?

  1s
• Which sublevels are present in the second energy level?

  S and P
• What sublevels are present in the third energy level?

  S, P, and D
• How many electrons can the S sublevel hold?

  2
• How many electrons can the P sublevel hold?

  6
• How many electrons can the D sublevel hold?

  10
• What is the total number of electrons in a Nitrogen atom?

  7
• What is the electron configuration for an atom of Nitrogen?

  1s$^2$ 2s$^2$ 2p$^3$
• What is the total number of electrons in an Aluminum atom?

  13
• What is the electron configuration for an atom of Aluminum?

  1s$^2$ 2s$^2$ 2p$^6$ 3s$^2$ 3p$^1$
• What is the atomic number of Iron (Fe)?

  26
• How many electrons does Fe 2+ have?

  24
• What is the electron configuration for Fe 2+?

  1s$^2$ 2s$^2$ 2p$^6$ 3s$^2$ 3p$^6$ 3d$^6$
• What should you do before writing the electron configuration of Fe 2+?

  Write the configuration of the parent atom
• What is the total number of electrons in a Chloride ion?

  18
• What is the electron configuration for the Chloride ion?

  1s$^2$ 2s$^2$ 2p$^6$ 3s$^2$ 3p$^6$
• What is the process for writing electron configurations for transition metals?

  • Write the configuration of the parent atom first
  • Subtract electrons based on the charge
  • Remove electrons from the highest energy level
• What is the process for writing electron configurations for non-transition metal ions?

  • Determine the total number of electrons in the ion
  • Write the configuration directly based on that number
  • No need to adjust from the parent atom
• What are the maximum electron capacities for each sublevel?

  • S: 2 electrons
  • P: 6 electrons
  • D: 10 electrons
  • F: 14 electrons
• What is the significance of the atomic number in electron configuration?

  • It indicates the number of protons
  • It equals the number of electrons in neutral atoms
• What is the significance of the mass number in electron configuration?

  • It represents the total number of protons and neutrons
• What is the difference in writing configurations for positive and negative ions?


  • Positive ions: subtract electrons
  • Negative ions: add electrons