Solutions: Atomic Structure

Q3.

(a) The most abundant isotope of cobalt is represented by z How many protons, neutrons and orbital electrons are there in a neutral atom of this element?

27 (protons) and 27 (electrons)
32 (neutrons)

(2 marks)

(b) How is the nuclide that has one less proton than the nickel nuclide, z, represented?

You should know that the proton number would be 27 - therefore it would be a cobalt nuclide (from part 'a') One less proton means the nucleon number would be one less too:

(correct nucleon number correct symbol and proton number )

(2 marks)

(c)

(i) The heaviest isotope of hydrogen, whose nucleon number is 3, is called tritium. How is tritium represented?


(ii) Calculate the charge per unit mass, in C kg–1, for a tritium nucleus.

charge/unit mass = 1/3 e/mp

= (1.6 x 10-19)/(3 x (1.67 x 10-27))
= 3.19 × 107 (C kg–1)

(allow C.E. from (i))

(3 marks)
(Total 7 marks)