MODULE 3

• Ion


  An atom or a group of atoms that has a net positive or negative charge
• Periodic Table and valence electrons


  • Elements on the same period have the same valence electrons
  • Elements on the same family have the same valence electrons
• Anion


  An ion that has more electrons than protons, giving it a net negative charge
• Fluorine ion


  Needs 4 more electrons to be stable
• Ions that can combine with oxygen ion to form an ionic compound

  • Calcium ion
  • Chlorine ion
• Families with elements having 5 valence electrons

  • Pnictogens
  • Halogens
• Polyatomic cation


  NH4+
• Anion in dry cell batteries

  Sulfur ion
• Aluminum ions needed to be stable with Sulfur ions

  3
• Chemical formula for compound in dry cell batteries

  Al2S3
• Octet rule


  An atom loses, gains, or shares electrons to have a full valence shell of 8 electrons
• Ion


  A charged atom or molecule due to an unequal number of electrons and protons
• Cation


  An ion that has lost one or more electrons, giving it a net positive charge
• Anion


  An ion that has gained one or more electrons, giving it a net negative charge
• Types of ions based on number of atoms

  • Monoatomic ions
  • Polyatomic ions
• Electrolytes are substances that conduct electricity when dissolved in water and are essential for bodily functions
• Strontium Ion

  Loses 2 electrons
• Strontium Ion


  Monoatomic
• Strontium Ion


  Cation
• Lead (IV) Ion


  Loses 4 electrons
• Lead (IV) Ion

  Monoatomic
• Lead (IV) Ion

  Cation
• NH4+


  Loses 1 electron
• NH4+

  Polyatomic
• NH4+

  Cation
• Hydroxide Ion


  Gains electrons
• Hydroxide Ion

  Polyatomic
• Hydroxide Ion

  Anion
• Ions


  • CN-
  • H3O+
  • Se2-
  • NH4+
  • Cl-
  • Cr2+
  • CO32-
  • Br-
  • Fe3+
  • Cs+
• Cations lose electrons, anions gain electrons
• Monoatomic ions are single atoms, polyatomic ions are made of multiple atoms
• Electrolytes are substances that conduct electricity when dissolved in water
• Electrolytes found in the body

  • Calcium Ion
  • Sodium Ion
  • Potassium Ion
  • Chloride Ion
• Calcium Ion


  Maintains strong bones and teeth
• Cs+ has 55 protons, 54 electrons, loses 1 electron
• Cr2- has 24 protons, 26 electrons, loses 2 electrons
• Cu2+ has 29 protons, 27 electrons, loses 2 electrons
• Cl- has 17 protons, 18 electrons, gains 1 electron
• NH4+

  Monoatomic cation
• Cr2O72-


  Polyatomic anion