Explain ionic, covalent, and metallic bonds, including their occurrence, properties, and relationships between structure and properties.

Here are the solutions to your questions:

1) Chemical Bonds

• Ionic Bond

  • Occurrence: Occurs between a metal and a non-metal. Electrons are transferred from the metal atom to the non-metal atom, forming positively charged cations and negatively charged anions. These oppositely charged ions are then held together by strong electrostatic forces of attraction.
  • Property: Ionic compounds typically have high melting and boiling points.
  • Relation: The strong electrostatic forces of attraction between the ions require a large amount of thermal energy to overcome, leading to high melting and boiling points.

• Covalent Bond

  • Occurrence: Occurs between two non-metal atoms. Atoms achieve a stable electron configuration by sharing one or more pairs of electrons.
  • Property: Simple molecular covalent substances typically have low melting and boiling points.
  • Relation: While the covalent bonds within the molecules are strong, the intermolecular forces of attraction between individual molecules are weak. Little energy is required to overcome these weak forces, resulting in low melting and boiling points.

• Metallic Bond

  • Occurrence: Occurs in metals. It is the electrostatic attraction between a lattice of positive metal ions and a 'sea' of delocalized electrons (valence electrons that are not associated with any one atom but are free to move throughout the structure).
  • Property: Metals are generally good conductors of electricity.
  • Relation: The delocalized electrons are free to move throughout the metallic structure and can carry an electrical charge, allowing metals to conduct electricity.

2) Bonding and Properties of Substances

• Magnesium Chloride ($\text{MgCl}_2$)

  • Type of Bonding: Ionic bonding. Magnesium ($\text{Mg}$) is a metal, and Chlorine ($\text{Cl}$) is a non-metal. Magnesium transfers two electrons to two chlorine atoms, forming $\text{Mg}^{2+}$ and $\text{Cl}^{-}$ ions.
  • Properties and Relation:
    1. High melting point: The strong electrostatic forces of attraction between the $\text{Mg}^{2+}$ and $\text{Cl}^{-}$ ions in the crystal lattice require a large amount of energy to overcome.
    2. Conducts electricity when molten or dissolved in water: In these states, the ions are free to move and can carry an electric current.

• Carbon Dioxide ($\text{CO}_2$)

  • Type of Bonding: Covalent bonding (simple molecular structure). Carbon ($\text{C}$) and Oxygen ($\text{O}$) are both non-metals, sharing electrons to form molecules.
  • Properties and Relation:
    1. Low melting and boiling point (sublimes): There are strong covalent bonds within each $\text{CO}_2$ molecule, but only weak intermolecular forces of attraction between the $\text{CO}_2$ molecules. Little energy is needed to overcome these weak forces.
    2. Does not conduct electricity: There are no free-moving ions or delocalized electrons to carry an electric charge.

• Calcium ($\text{Ca}$)

  • Type of Bonding: Metallic bonding. Calcium is a metal.
  • Properties and Relation:
    1. Good electrical conductivity: The delocalized electrons in the 'sea' are free to move and carry an electric charge throughout the metal.
    2. Malleable and ductile: The layers of positive calcium ions can slide past each other without breaking the metallic bond because the 'sea' of delocalized electrons can rearrange to maintain the electrostatic attraction.