Formation of ions

• What is an ion?

  An ion is a charged particle.
• What are two examples of ions mentioned in the material?

  Sodium ion (Na⁺) and hydroxide ion (OH^-).
• How are ions formed?

  Ions are formed when atoms gain or lose electrons.
• Why do atoms gain or lose electrons?

  Atoms gain or lose electrons to have a full outer shell for stability.
• What does the group number in the periodic table indicate?

  The group number indicates how many electrons the atoms of that group have in their outermost shell.
• How many electrons do group one elements have in their outermost shell?

  Group one elements have one electron in their outermost shell.
• Why are group one and group two elements more likely to form ions?

  They only need to lose or gain one or two electrons, which requires less energy.
• What type of ions do group one elements form?

  Group one elements form one plus ions.
• What type of ions do group two elements form?

  Group two elements form two plus ions.
• What type of ions do group six elements form?

  Group six elements gain two electrons to become two minus ions.
• What type of ions do group seven elements form?

  Group seven elements gain one electron to become one minus ions.
• Why do elements in groups three, four, and five rarely form ions?

  They would have to lose or gain three or four electrons, which requires a lot of energy.
• How can we represent the formation of ions in chemical equations?

  We can write equations to show the gain or loss of electrons.
• How would you write the equation for sodium forming a sodium ion?

  Na goes to form Na⁺ + e^-.
• How would you write the equation for chlorine forming a chloride ion?


  Cl + e^- goes to form Cl^-.
• How would you write the equation for magnesium forming a magnesium ion?

  Mg goes to form Mg²⁺ + 2e^-.
• How would you write the equation for oxygen forming an oxide ion?

  O + 2e^- goes to form O^2-.
• What is the process of ion formation in relation to stability?

  • Atoms gain or lose electrons.
  • This occurs to achieve a full outer shell.
  • A full outer shell leads to greater stability.
• What are the differences in ion formation between groups one, two, six, and seven compared to groups three, four, and five?

  • Groups one and two easily lose electrons (1 or 2) to form ions.
  • Groups six and seven gain electrons (2 or 1) to form ions.
  • Groups three, four, and five require more energy to lose or gain 3 or 4 electrons, making ion formation rare.