Electron configuration

• What are the arrangements of electrons in an atom called?

  Electron configurations
• What are electron shells?

  They are energy levels where electrons are arranged.
• What are subshells made up of?

  Subshells are made up of electron orbitals.
• How many electrons can each orbital hold?

  Each orbital can hold 2 electrons.
• How do the two electrons in each orbital spin?

  They spin in opposite directions.
• What are orbitals?

  Regions of space where electrons are most likely to be found.
• What is the composition of shell 2?

  Shell 2 is made up of one s orbital and three p orbitals.
• What are the four types of subshells?

  s, p, d, f
• How many electrons can each type of subshell hold?

  s subshells can hold 2, p subshells can hold 6, d subshells can hold 10.
• What happens if an orbital is full?

  The two electrons will have opposite spins.
• How do we represent each electron in an orbital?

  We use half arrows to represent each electron.
• What is the subshell filling order for electrons?

  1. s subshell = 1 orbital (2 electrons)
  2. p subshell = 3 orbitals (6 electrons)
  3. d subshell = 5 orbitals (10 electrons)
  4. Filling order: 1s -> 2s -> 2p -> 3s -> 3p -> 4s -> 3d -> 4p
• What does the Aufbau Principle state?

  Electrons enter the lowest energy orbital available.
• What is Hund's Rule?

  Electrons prefer to occupy empty orbitals before pairing up.
• How many electrons does silicon have?

  Silicon has 14 electrons.
• What is the electron configuration for silicon?

  1s² 2s² 2p⁶ 3s² 3p²
• How many electrons does calcium have?

  Calcium has 20 electrons.
• What is the electron configuration for calcium?

  1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
• What happens to the highest energy electrons when an ion is formed?

  They are lost when an ion is formed.
• Which electrons are lost first in the formation of an ion?

  4s electrons are lost before 3d electrons.
• How many electrons does magnesium have?

  Magnesium has 12 electrons.
• What is the electron configuration for Mg²⁺?

  1s² 2s² 2p⁶
• How many electrons does iron have?

  Iron has 26 electrons.
• What is the electron configuration for Fe?

  1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶
• What is the electron configuration for Fe³⁺?

  1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵
• How do the electron configurations of chromium and copper differ from expected structures?

  They have unexpected electron structures due to stability preferences.
• What is the electron configuration for chromium?

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

  1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d¹⁰