Answer : Option 1) An atom is mainly empty space, and the nucleus has a positive charge.
Explanation : The gold foil experiment done by scientist Rutherford revealed that atoms are the smallest unit of any element which consists of large empty space in it with the nucleus was concentrated in the center of the atom with mostly positive charge around it and virtually contains all the mass of the atoms and there are also negatively charged electrons which revolves in orbits around the nucleus.