chapter 7

• What do elements in a group have in common?

  Same number of outer-shell electrons
• What are groups in the periodic table?

  Vertical columns of elements
• What does the number of the period indicate?

  Highest energy electron shell number
• What is periodicity?

  A repeating periodic pattern
• What is the first ionisation energy?

  Energy to remove one electron from an atom
• What factors affect ionisation energy?

  Atomic radius, nuclear charge, electron shielding
• What is the second ionisation energy?

  Energy to remove one electron from 1+ ions
• What can successive ionisation energies predict?

  Number of outer shell electrons and group
• How does atomic radius change down a group?

  Atomic radius increases due to more inner shells
• Why does first ionisation energy decrease down a group?

  Nuclear attraction on outer electrons decreases
• What happens to first ionisation energy across a period?

  First ionisation energy increases due to nuclear charge
• Why is the first ionisation energy of boron less than that of beryllium?

  2p electron in boron is easier to remove
• What does the fall in first ionisation energy from nitrogen to oxygen indicate?

  Start of electron pairing in p-orbitals
• Why is it easier to remove an electron from oxygen than nitrogen?

  Paired electrons in oxygen repel each other
• What characterizes a metal structure?

  Delocalised electrons spread across the structure
• What is metallic bonding?

  Electrostatic force between cations and electrons
• What is a giant metallic lattice?

  Structure held together by metallic bonds
• Why do metals have high boiling and melting points?

  Strong metallic bonds require much energy to break
• Why do metals conduct electricity well?

  Delocalised electrons can carry a charge
• How are non-metals like boron, carbon, and silicon bonded?

  By strong covalent bonds in a giant lattice
• What is the melting and boiling point of giant covalent lattices?

  High due to strong covalent bonds
• Why are giant covalent lattices mostly insoluble?

  Covalent bonds are too strong to break
• Why can't diamond and silicon conduct electricity?

  All outer shell electrons are involved in bonding
• What allows graphene and graphite to conduct electricity?

  Presence of delocalised electrons
• What does the sharp change in melting points indicate?

  Change from giant to simple molecular structures