PeriodicityEdexcel A-Level Chemistry: Mind map

Exam questions on Periodicity

1. The melting temperatures of the Period 3 elements, in °C, are: Na 98, Mg 650, Al 660, Si 1410, P 44, S 115, Cl −101 and Ar −189.
   Explain why aluminium has a much higher melting temperature than phosphorus.2 marks
2. Phosphorus exists as P₄ molecules, sulfur as S₈ molecules and chlorine as Cl₂ molecules. Their melting temperatures are 44 °C, 115 °C and −101 °C respectively.
   Explain why sulfur has a higher melting temperature than phosphorus.2 marks
3. The first ionisation energies of the Period 2 elements, in kJ mol⁻¹, are: Li 520, Be 900, B 801, C 1086, N 1402, O 1314, F 1681 and Ne 2081.
   Explain the general increase in first ionisation energy from lithium to neon.3 marks