June 2024 QP - Paper 1 AQA Chemistry AS-level

Section A Answer all questions in this section. 0 1 This question is about atomic structure. In the nineteenth century JJ Thomson discovered the electron. He suggested that negative electrons were found throughout an atom like ‘plums in a pudding of positive charge’. Figure 1 shows an atom of element R using the ‘plum pudding’ model. An atom of R contains seven electrons. Figure 1 0 1 . 1 State two differences between the ‘plum pudding’ model and the model of atomic structure used today. [2 marks] 1 0 1 2 . 2 Deduce the full electron configuration of an atom of element R. [1 mark] 0 1 . 3 Identify R and deduce the formula of the compound formed when R reacts with the Group 2 metal in the same period as R. [1 mark] *02* This question is about sodium fluoride (NaF). Some toothpastes contain sodium fluoride. The concentration of sodium fluoride can be expressed in parts per million (ppm). 1 ppm represents a concentration of 1 mg in every 1 kg of toothpaste. 0 2 . 1 A 1.00 g sample of toothpaste was found to contain 2.88 x 10–5 mol of sodium fluoride. Calculate the concentration of sodium fluoride, in ppm, for the sample of toothpaste