Physical properties of Period 3 elementsAQA A-Level Chemistry: Mind map

Exam questions on Physical properties of Period 3 elements

1. The atomic radius of the elements decreases across Period 3, from 0.186 nm for sodium to 0.099 nm for chlorine.
   Explain why the atomic radius decreases from sodium to chlorine.2 marks
2. The first ionisation energies of the Period 3 elements (in kJ mol⁻¹) are: Na 496, Mg 738, Al 578, Si 786, P 1012, S 1000, Cl 1251, Ar 1521.
   Explain why the first ionisation energy of argon is much higher than that of sodium.2 marks
3. The melting points of four Period 3 elements are: sodium 371 K, magnesium 923 K, aluminium 933 K and silicon 1687 K.
   Explain why magnesium has a higher melting point than sodium.3 marks