Bonding + properties

• The type of bond formed in a substance depends on the elements involved and their position in the periodic table
• To find the formula of an ionic bond, the ratio of metal ions to non-metal ions in the lattice structure is counted
• Modeling ionic bonding

  Ions arranged in a crystalline lattice structure with strong electrostatic forces of attraction between oppositely charged ions
• Properties of ionic compounds

  • High melting point
  • Brittleness
  • Ability to conduct electricity when liquid or in an aqueous solution
• Formation of ionic bond

  Attraction between oppositely charged ions formed by the transfer of electrons from one atom to another
• Type of bonding within ionic, metallic, and covalent substances


  • Explains their physical properties including melting and boiling point, thermal and electrical conductivity, strength, and hardness
• Ionic bonding


  Transfer of electrons from one atom to another to achieve an inert gas configuration, forming ions
• Different types of bonding

  • Ionic compounds
  • Covalent compounds/substances
  • Metals
• Bonds are electrostatic forces (attractions between positive and negative charges) which hold atoms together
• When naming ionic compounds, cations are listed first and anions are listed second. Metals maintain their elemental name as the cation, while non-metal endings change to '-ide'
• Formation of sodium chloride

  • Each sodium atom transfers an electron to a chlorine atom resulting in a sodium ion and a chloride anion
• Naming ionic compounds

  • NaCl - Sodium chloride
  • MgO - Magnesium oxide
  • Na2O - Sodium oxide
  • MgCl2 - Magnesium chloride
  • Li3N - Lithium nitride
  • CaS - Calcium sulfide
  • NiBr2 - Nickel(II) bromide
• Atoms form bonds to become more stable - by losing, gaining, or sharing electrons
• Properties of ionic compounds

  • High boiling and melting points
  • Electrostatic forces of attraction between oppositely charged ions lead to the formation of ions
  • Ionic compounds form crystals
  • Ionic compounds are brittle and break into small pieces easily
  • Do not conduct electricity in a solid state but they do conduct electricity in the molten state
  • Electrovalent compounds usually dissolve in water and are insoluble in solvents like oil, petrol, kerosene, etc
• Explanation of the properties of metals
• Solubility of ionic compounds
• Conductivity of metals
• Strength and Hardness of metals
• Naming Ionic Compounds

  1. The metal name stays the same

  2. The non-metal ending changes to ‘-ide'
• Covalent Bonding
• Examples of Naming Ionic Compounds

  • NaCl - Sodium chloride
  • MgO - Magnesium oxide
  • Na2O - Sodium oxide
  • MgCl2 - Magnesium chloride
  • Li3N - Lithium nitride
  • CaS - Calcium sulfide
  • NiBr2 - Nickel(II) bromide
• Mechanical properties of ionic compounds
• Formation of covalent bonds
• Melting point and boiling point of ionic compounds
• Properties of metals

  • Good conductor of electricity
  • Good conductor of heat
  • Hard and not brittle
  • Malleable
  • Ductile
• Electrical conductivity of ionic compounds
• Properties of covalent substances: Bonds where electrons are shared between atoms. Due to the sharing of electrons, they exhibit characteristic physical properties that include lower melting points and electrical conductivity compared to ionic compounds
• Information about bond forces between atoms in exothermic/endothermic reactions
• Covalent compounds do not conduct electricity and heat transfer is less efficient compared to ionic compounds
• Covalent Molecules

  1. In a solid or liquid, no covalent bonds bond the distinct molecules together

  2. Weak intermolecular forces between molecules

  3. Differences in boiling points due to strength of intermolecular interactions
• Covalent Network

  1. Group 4 elements can exist as a covalent network structure

  2. Have 4 valence electrons which can be shared with other atoms of the same element

  3. Allotropes are different structural forms of an element consisting of identical atoms

  4. Different arrangement gives them different physical properties
• Covalent Networks

  • Poor electrical conductivity
  • Hardness and strength due to strong covalent bonds
• Covalent substances

  • Elements likely to form covalent network substances: Boron, Carbon, Silicon
  • High melting points due to strong bonds
  • Examples include diamond and graphite
• Covalent Bonding

  • Intramolecular forces – forces within a molecule
  • Strong and require energy to break them
• Covalent Bonding


  Sharing of electrons to create stability – outer shell of 8 electrons complete
• Covalent Bonding

  1. High melting / boiling points due to the energy required to break bonds

  2. Diamond has a melting point of 3500oC
• Link to complete Socrative quiz: https://b.socrative.com/teacher/#import-quiz/70084402
• Atoms form bonds to become more stable by

  Losing, gaining or sharing electrons
• Ionic bonds are formed between

  Metallic and non-metallic atoms ONLY
• Formation of sodium chloride

  • This diagram highlights the formation of NaCl as you can see from the picture the electron on the outermost shell of the sodium atom transfers to chlorine atom. Consequently, chlorine is gaining an electron and sodium is losing an electron. Both ions of have now a full valence shell and we can see that a NaCl has been produced