In the rutherford famous gold fail experiment most of the - particle pass through the tail undeflected signifying that most of the space inside an atom is empty and many of them get deflected by a very small angle implying that the nature of the charge in the atom (nucleus), located at the centre should be same as the - particles. i.e positive. out of 8,000 - particle, one of them gets deflected for almost , signifies that very dense mass is situated at the centre of the atom.