What questions and/or thoughts prompted rutherford’s famous alpha particle scattering experiment?

Before Rutherford, JJ Thompson came up with the "plum pudding" model, in which the atom is composed of electrons surrounded by positive charge to balance the electrons’ negative charges. Rutherford's experiment disproved this model, by showing there's a small, high-energy nucleus in the center of an atom.

All the elements are arranged by melting points on the periodic table. in row they go from metals to gasses. in the row from sodium to argon, sodium is more reactive than the one on its right, magnesium.