JPJC 2026 Atomic Structure Assignment

Jurong Pioneer Junior College 2026 JC1 H2 Chemistry: Atomic Structure 1 2026 JC1 H2 Chemistry (9476) Topical Assignment Topic 1: Atomic Structure Name : _____________________________________ 10 Class : 26S _______ Date : ____________ Duration : 15 minutes Answer all questions in the space provided. 1 (a) It is widely accepted that elements up to iron are primarily formed through nuclear fusion in stars. The graph below shows the variation of first ionisation energies across Period 2. Figure 1.1 (i) State and explain the general trend of first ionisation energies across Period 2. [2] (ii) Briefly explain why there is a drop in first ionisation energy from the element nitrogen, N, to the element oxygen, O. [1]

2 (iii) Give an equation that represents the third ionisation energy of Be. [1] (iv) Figure 1.2 shows how the third ionisation energies vary across Period 2 elements from Lithium to Neon. Explain the reason for the most significant drop in third IE from Be to B. [1] Figure 1.2 3rd ionisation energy / kJ mol-1

Jurong Pioneer Junior College 2026 JC1 H2 Chemistry: Atomic Structure 3 (b) All elements are assigned a value of electronegativity on the Pauling scale. Table 1.1 shows the electronegativity values of nitrogen and phosphorus. Table 1.1 atom electronegativity / pauling units nitrogen 3.0 phosphorus 2.2 Explain why the electronegativity value of phosphorus is lower than that of nitrogen. [2] (c) Chromium is the 21st most abundant element in Earth's crust. (i) Write the full electronic configuration of Cr+. [1] (ii) Using the axes provided below, draw the shape of the 3py orbitals in Cr+. Label the axes and your orbitals clearly. [1] (d) When a beam of 7Li+ and 16O2− are passed through the same electric field, they behave differently. Given that the angle of deflection of 7Li+ is +15.0o, calculate the angle of deflection for 16O2−. [1]