Why was Rutherford's gold foil experiment important?
Rutherford's experiment showed that atoms consisted of a dense mass which was surrounded by mostly empty space - the nucleus!
Rutherford's experiment utilized positively charged alpha particles (He with a +2 charge) which were deflected by the dense inner mass (nucleus). The conclusion that could be formed from this result was that atoms had an inner core which contained most of the mass of an atom and was positively charged.
Prior models of the atom (Plum pudding) postulated that negative particles (electrons) were distributed randomly though a positively charged substance. Think chocolate chips (for electrons) distributed randomly in cookie dough (positive substance)