5 - Electrons & Bonds

• atomic orbital - a region of space around the nucleus that can hold up to 2 electrons with opposite spins
• what are the 4 types of orbital (lowest energy level first)

  • s
  • p
  • d
  • f
• dative covalent bond - a shared pair of electrons where one atom donates both electrons
• ionic lattice - a regular, repeating pattern of oppositely charged ions, held together by strong electrostatic forces
• explain why the boiling point of PH3 is lower than NH3

  • NH3 has hydrogen bonding (PH3 does not)
  • hydrogen bonding is stronger AND
  • requires more energy to overcome
• explain why the boiling point of PH3 is lower than AsH3

  • As has more electrons than P, so in AsH3 there are
  • stronger / more London forces
  • stronger / more induced dipole-dipole interactions
  • so more energy is required to overcome these forces