Formation of Ions

• What is an ion?

  A charged particle
• How are ions formed?

  Atoms gain or lose electrons
• Why do atoms form ions?

  To have a full outer shell for stability
• What does the group number in the periodic table indicate?

  Electrons in the outermost shell
• How many electrons do group one elements have in their outermost shell?

  One electron
• How many electrons do group two elements have in their outermost shell?

  Two electrons
• Why are group one elements likely to form ions?

  They only need to lose one electron
• How do group two elements become ions?

  They lose two electrons to become two plus ions
• How do group six elements become ions?

  They gain two electrons to become two minus ions
• How do group seven elements become ions?

  They gain one electron
• Why do elements in groups three, four, and five rarely form ions?

  They require a lot of energy to lose or gain electrons
• How do we represent the loss of electrons in a chemical equation?

  Place the electron on the right of the reaction
• How do we represent the gain of electrons in a chemical equation?

  Place the electron on the left of the reaction
• What ion does magnesium form when it loses electrons?

  A two plus ion
• How do we write the equation for magnesium forming a two plus ion?

  Mg goes to form Mg²⁺ plus two electrons
• How do we write the equation for oxygen forming a two minus ion?

  Oxygen plus two electrons goes to form an oxygen two minus ion
• What are the key points about ion formation in relation to energy requirements?

  • Atoms lose or gain electrons for stability
  • Group one and two elements require less energy
  • Groups three, four, and five require more energy
  • Energy requirements affect ion formation likelihood
• What are the differences in ion formation among different groups in the periodic table?

  • Group one: Lose one electron easily
  • Group two: Lose two electrons easily
  • Group six: Gain two electrons easily
  • Group seven: Gain one electron easily
  • Groups three, four, five: Rarely form ions due to high energy requirement