Which part of the periodic table contains elements with the greatest metallic properties?

The bottom of group 1. Francium (or Fr) is the element with the greatest metallic properties.

Francium is not a naturally-occurring element, however. It is man-made. There is an isotope of francium that exists naturally, but it's half life is so short that it decays almost instantly into a different element.

The naturally-occurring element with the highest metallic properties is cesium (or Cs), located right above francium.

Metallic characteristics decrease as you move from left to right on the periodic table.