Osmium i think
Because most things are made of metal.
There are a large number of metals present on periodic table. So they are most abundant.
This element is francium in the first group of periodic table.
Platinum is the least reactive metal.
Iron
Francium (Fr)
Hydrogen.
Francium is the most reactive metal.
It would be a metal . The metal family takes up most of the periodic table
fluorine is the most reactive non metal in the periodic table.
The Alkali metals are the most reactive group of metals in the Periodic Table. Of these Francium is the most reactive metal of all.
sodium