This rare metal has the lowest electronegativity on the periodic table. With an electronegativity number of 0.7 this element donates it's electron very easily to the higher electronegative nonmetals.
Fluorine is the most reactive element.
Fluorine(F2) is the most reactive element, known to react with even Xenon, Krypton, Gold, Platinum, etc.
If by vital you mean most reactive, then the metal francium, Fr, is the most reactive element.
Fluorine
Potassium is most reactive with the element Oxygen. However, it should be noted that it is most reactive with a non-element: Water.
The most reactive is fluorine.
No, the opposite of that.
Potassium is the most reactive element with oxygen, readily reacting to form potassium oxide.
Fluroine is the most reactive non-metal.
Elements are more reactive as you go down the periodic table and to the left.
Fluorine
Chlorine is the most reactive gas element. Chlorine is in the halogen family.