Formation of ions

• What are ions in chemistry?


  Charged particles that can be single atoms or groups of atoms
• How do ions form?


  By the transfer of electrons between atoms
• What is the charge of a chloride ion?

  Cl^–
• Why do atoms lose or gain electrons to form ions?


  To achieve a full outer shell, resembling a noble gas
• What happens when metals form ions?


  They lose electrons to form positive ions
• What happens when non-metals form ions?


  They gain electrons to form negative ions
• How is the charge of an ion determined?


  It is equal to the number of electrons lost or gained
• Which groups of elements are most likely to form ions?

  Groups 1, 2, 6, and 7
• What type of ions do Group 1 and 2 elements form?


  Positive ions (cations)
• What type of ions do Group 6 and 7 elements form?


  Negative ions (anions)
• How can you determine what ions most elements form?


  By looking at the periodic table
• Why do elements in the same group form ions with the same charge?


  They have the same number of outer electrons
• What charge do Group 1 elements form?


  1+ ions
• What charge do Group 2 elements form?


  2+ ions
• What charge do Group 6 elements form?


  2– ions
• What charge do Group 7 elements form?


  1– ions
• What happens to a sodium atom (Na) when it forms a sodium ion?


  It loses 1 electron to form Na⁺
• What happens to a magnesium atom (Mg) when it forms a magnesium ion?


  It loses 2 electrons to form Mg²⁺
• What happens to a chlorine atom (Cl) when it forms a chloride ion?


  It gains 1 electron to form Cl^–
• What happens to an oxygen atom (O) when it forms an oxide ion?


  It gains 2 electrons to form O^2–
• Why do elements want to have a full outer shell?

  • To achieve stability
  • To resemble noble gas electronic structures
  • To minimize energy levels
• How do you predict the charge of an ion formed by an element?


  1. Identify the group of the element in the periodic table.
  2. Determine the number of electrons lost or gained to achieve a full outer shell.
  3. The charge of the ion corresponds to the number of electrons lost (positive) or gained (negative).
• What is formed when clams are involved in the process described?


  Formation of ions
• What is a single atom represented by in the study material?


  [Na]
• What is a charged particle called?


  Ion
• What is the group of atoms mentioned in the study material?

  Group of clams
• What is the formula for hydroxide ion?


  [OH]
• What is required for atoms to lose or gain electrons?

  Energy
• Why do some atoms only have to lose or gain 1 or 2 electrons?


  Because they require less energy to do so
• What is the term for the equations that represent the gain or loss of electrons?


  Equations of ion formation
• What happens to sodium in the equation Na → Na⁺ + e⁻?

  Sodium loses an electron
• In the equation Cl + e⁻ → Cl⁻, what does chlorine do?


  Chlorine gains an electron
• What can sometimes happen to atoms regarding electrons?


  They can lose or gain multiple electrons
• What is the equation for magnesium losing two electrons?


  Mg → Mg²⁺ + 2e⁻
• What is the charge of the magnesium ion when it loses two electrons?


  [Mg]²⁺
• What is the charge of the ion formed when magnesium loses two electrons?


  2+