In the short form: elements are striving to completely fill valence shells of electrons to reach a quantumly stable energy state. They react to take electrons away from elements willing to give up electrons or share outer shell electrons with elements they aren't strong enough to steal from.
Elements are more reactive as you go down the periodic table and to the left.
Potassium is the most reactive element with oxygen, readily reacting to form potassium oxide.
Plutonium is not highly reactive under normal conditions. It is a relatively stable element that does not react readily with air or water. However, it can be reactive in certain chemical reactions or when exposed to high-energy particles.
This is called a displacement reaction. It occurs when a more reactive element displaces a less reactive element from its compound during a chemical reaction.
A scientist might store a super reactive element with a noble gas as a way to prevent chemical reactions with the surrounding environment. Noble gases are inert and non-reactive, providing a stable environment for storing highly reactive elements. This helps to ensure the safety of handling and storage of the reactive element.
Fluorine is the most reactive element.
The element Californium is reactive.
Hydrogen is not only the lightest element of all, it is also very reactive.
Fluorine(F2) is the most reactive element, known to react with even Xenon, Krypton, Gold, Platinum, etc.
An element is said to be chemically reactive when it combines with another element. These two elements will create a new compound.
If by vital you mean most reactive, then the metal francium, Fr, is the most reactive element.
Potassium is most reactive with the element Oxygen. However, it should be noted that it is most reactive with a non-element: Water.
copper is very un-reactive. lead is more reactive.
Fluorine
Yes. it is.
XENON
I dont think i am sure about that