Rutherford selected gold for alpha particle scattering experiment because
(i) Gold was cheaper and brittle.
(ii) Gold can be easily hammered into a thin layer of 1000 atoms without breaking it.
(iii) Gold does not chemically react with alpha particle.
Gold can be easily hammered into a thin layer of 1000 atoms without breaking it and also does not chemically react with alpha particle.
Rutherford selected a gold foil because gold is most malleable metal i.e gold can be beaten up into a thin layer of 1000 atoms without cracking or breaking. And gold does not absorb or chemically react with alpha particle.
But, on the other hand gold is very rare and relatively expensive to produce.