There are many examples. Ni is a example element.
Magnesium is an Alkaline Earth element. It is a metal, and is very reactive.
A reactive non metal is an element that can gain the electrons or is more electronegative
Chlorine is a very reactive non-metal. It readily combines with other elements to form compounds and is highly electronegative, meaning it has a strong tendency to gain electrons in chemical reactions.
Start with a more reactive metal or element and a less reactive metal or element in solution or in contact with each other. The more reactive metal will displace the less reactive metal from its solution or compound, resulting in a new compound containing the more reactive metal and a separate less reactive metal. The displacement reaction follows the activity series of metals, where more reactive metals displace less reactive metals from their compounds.
A reactive non-metal.
If by vital you mean most reactive, then the metal francium, Fr, is the most reactive element.
Cesium is the most chemically reactive metal.
Barium is the element that produces yellow-green fireworks. It is a highly reactive metal that is commonly used in fireworks to create vibrant green colors.
Carbon is a very reactive nonmetal but not the most reactive.
Sodium is not an unreactive element. It is a highly reactive metal that readily forms compounds with other elements, especially in the presence of water to form sodium hydroxide and hydrogen gas. Sodium is stored under oil to protect it from reacting with air or moisture.
The most reactive non-metal is fluorine. It is often nicknamed the 'Tyrannosaurus Rex' of the elements because of its reactivity. NB . Oxygen ,which we breath, is also a very reactive element. If it wasn't so reactive we would probably die.
Hydrogen is not only the lightest element of all, it is also very reactive.