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Solutions: Atomic Structure

Q6.

(a) How many protons, neutrons and electrons are there in an atom of ?

6 (protons) and 6 (electrons)
8 (neutrons)

(2)

(b) The atom loses two electrons. For the ion formed;

(i) calculate its charge in C,

Q = (2 × 1.6 × 10–19) = 3.2 × 10–19 C


(ii) state the number of nucleons it contains,

14


(iii) calculate the charge to mass ratio in C kg–1.

m = 14 × 1.67 × 10–27 kg
Q/m = (answer to (i))/(14 × 1.67 × 10–27) = 1.4 × 107 C kg–1 (1.37 ×107 C kg–1)
(allow C.E for values from (i) and (ii))

(4)
(Total 6 marks)