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Solutions: Atomic Structure

Q9.

(a) A stable atom contains 28 nucleons.

Write down a possible number of protons, neutrons and electrons contained in the atom.

number of protons = number of electrons (e.g.14)
number of protons + number of neutrons = 28

(2)

(b) An unstable isotope of uranium may split into a caesium nucleus, a rubidium nucleus and four neutrons in the following process.

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(i) Explain what is meant by isotopes.

Isotopes are nuclei with nuclei with the same number of protons but different number of neutrons/nucleons

(ii) How many neutrons are there in the z nucleus?

137 – 55 = 82

(iii) Calculate the charge to mass ratio, in C kg–1, for thez nucleus.

Q/m = (92 x 1.6 x 10-19)/(236 x 1.67 x 10-27) = 3.73 × 107 C kg–1

 

(iv) Determine the value of X for the rubidium nucleus.

X = 236 – 137 – 4 = 95

(6)
(Total 8 marks)