Questions regarding ionisation energy
1: Why does Ne have a higher first ionisation energy than Ar ?
2: Why do first ionisation energies increase from Al to Si to P ?
3: Why is the first ionisation energy of Na much less than that of Ne ?
Questions regarding atomic radius
4: Explain why the radius of the atoms in Period 3 decreases across the period, even though the numbers of protons and neutrons increase.
Questions regarding melting and boiling points
5: The boiling points of sodium, magnesium and aluminium are 883ºC, 1107ºC, and 2467ºC respectively. Explain this trend.
6: Silicon and phosphorus are both covalently-bonded solid elements at room temperature. The melting point of silicon is 1410ºC while that of phosphorus is 44ºC. Explain this difference.
7: The boiling points of the Period 2 elements nitrogen and fluorine are -195ºC and -188ºC respectively. The corresponding elements in Period 3 do not show the same increase, phosphorus boils at 281ºC and chlorine at -35ºC. Explain why this non-periodic behaviour occurs.
Other periodic properties – electrical conductivity
8: Which of the metals potassium or calcium has the greater electrical conductivity. Explain your answer.
9: Explain why the electrical conductivity of aluminium is much higher than than of silicon even though and aluminium atom as 3 outer-shell electrons and a silicon atom has 4 outer-shell electrons.
