PeriodicityEdexcel A-Level Chemistry: Flashcards
What these 12 flashcards ask
- What is periodicity?
- Why does melting temperature rise from Na to Al?
- Why does silicon have a very high melting temperature?
- What type of structure do P₄, S₈ and Cl₂ have?
- Why does sulfur melt at a higher temperature than phosphorus?
- Why does argon have the lowest melting temperature in period 3?
- What is broken when a simple molecular substance melts?
- What is the general trend in atomic radius across period 3?
- Why does first ionisation energy generally increase across a period?
- Why is the first IE of Al lower than that of Mg?
- Why is the first IE of S lower than that of P?
- Which period 2 elements have giant covalent structures?
Exam questions on Periodicity
- 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
- 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
- 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
Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).