across period 2

• Li to Be

  • melting points increase from Li to Be because the strength of the metallic bonding increases, so more energy is needed to break the metallic bonds
• B to C

  • Boron and Carbon have much higher melting points.
  • B and C are giant macromolecular structures held together by many strong covalent bonds.
  • These require a lot of energy to break hence B and C have very high melting points. 
  • Carbon contains stronger bonds than Boron, so has a higher melting point.
• N to Ne

  • Nitrogen, oxygen and fluorine all exist as diatomic simple covalent molecules
  • melting and boiling points don’t depend on the strength of the covalent bonds they form, but the strength of the induced dipole dipole intermolecular forces