copper
any element that is a non metal will do
Metal, like sodium.
A new element is most likely metal because it gives people the most boners
This element is iron.
The most abundant metal in the earth crust is aluminium.
aluminum that's aluminum for the brits aluminum is the most abundant metal in the earth's crust, it is never found free in nature. All of the earth's aluminum has combined with other elements to form compounds. Two of the most common compounds are alum, such as potassium aluminum sulfate and aluminum oxide About 8.2% of the earth's crust is composed of aluminum."
Francium
Lithium. Practically every metal combined with fluorine will give you an ionic compound. Some transition metals have volatile penta and hexafluorides and these are bonded with polar covalent bonds.
Most of the metals can occur in the native and combined forms.
Sodium is a highly reactivated element. It shows +1 generally when combined.
If it is a metal it is a reactive element.
If by vital you mean most reactive, then the metal francium, Fr, is the most reactive element.