On the basis of Thomson's model of an atom, explain how an atom as a whole is neutral.

(a) Name an element which does not contain neutron.

(b) If an atom contains one electron and one proton, will it carry any charge or not?

(a) Which metal did Rutherford select for his α-particle scattering experiment and why ?

(b) What do you think would be the observation of α-particle scattering experiment if carried out on

(i) heavy nucleus like platinum

(ii) light nuclei like lithium.

Name the sub-atomic particle whose charge is

(a) +1

(b) -1

(c) 0.