Atomic Structure

Q15. The table belowcontains five statements that refer to isotopes and some radium isotopes.

Isotope with the smallest mass number
Isotope with most neutrons in nucleus
Isotope with nucleus which has the largest specific charge
Isotope decays by β– decay to form
Isotope decays by alpha decay to form

 

(a) Complete the table by ticking one box in each row to identify the appropriate isotope for each statement. The first row has been completed for you.

[4 marks]

(b)

(i) An atom of one of the radium isotopes in the table is ionised so that it has a charge of +3.2 × 10–19 C. State what happens in the process of ionising this radium atom.

[1 mark]

(ii) The specific charge of the ion formed is 8.57 × 105 C kg–1. Deduce which isotope in the table has been ionised. Assume that both the mass of a proton and the mass of a neutron in the nucleus is 1.66 × 10–27 kg.

The charge on the ion is given you in part (i).

[3 marks]

(Total 8 marks)