EL5

• How can covalent bonds be represented?

  Using dot and cross diagrams or a straight line.

  
• What are dative covalent bonds?

  • Form when both electrons in the shared pair come from one atom.
  • Indicated with an arrow from the lone electron pair.

  
• What happens when ammonia (NH₃) forms a dative bond?

  It forms an ammonium ion (NH₄⁺) with a H⁺ ion.

  
• What characterizes simple covalent substances?

  • Consist of covalently bonded molecules.
  • Held together by intermolecular forces.
• How is the shape of a simple molecule determined?

  • By the number of electron pairs around the central atom.
  • By the repulsion between bonding and lone pairs.
• What is the effect of lone pairs on bond angles?

  Each lone pair reduces the bond angle by 2.5°.
• What steps are involved in determining the shape of a molecule?

  1. Find the number of electron pairs.
  2. Determine the number of bonding pairs and lone pairs.
  3. Bonding pairs indicate the basic shape, while lone pairs indicate additional repulsion.
• How is bond length defined?

  Bond length is the average distance between two nuclei in a covalent bond.
• What is the bond angle in a linear molecule?

  The bond angle in a linear molecule is 180°.
• What is the bond angle in a V-shaped molecule with 2 bonding pairs and 2 lone pairs?

  The bond angle in a V-shaped molecule is 104.5°.
• What is the bond angle in a trigonal planar molecule?

  The bond angle in a trigonal planar molecule is 120°.
• What is the bond angle in a triangular pyramid molecule?

  The bond angle in a triangular pyramid molecule is 107°.
• What is the bond angle in a tetrahedral molecule?

  The bond angle in a tetrahedral molecule is 109.5°.
• What characterizes giant covalent structures?

  Giant covalent structures consist of atoms bonded in a giant lattice with multiple strong covalent bonds.