Sodium I think
Cesium is the most chemically reactive metal.
The most chemically reactive metals are the alkali metals. Francium is the most reactive of these and of all metal (although it is present on earth only in exceedingly small quantities, due to its radioactivity).The most reactive element available in useful quantities in Flourine.
Yes, chlorine is chemically reactive. It is a highly reactive nonmetal and readily forms compounds with other elements.
Noble gases, such as helium, neon, and argon, are the least chemically reactive elements. They have a full outer shell of electrons, making them extremely stable and unlikely to form chemical bonds with other elements.
Caesium. Francium may be more reactive but it is radioactive as well as chemically very reactive and so there are many uncertainties regarding its properties.
The most chemically active non-metal, and the most reactive element overall, is fluorine. Fluorine has an extremely high electronegativity, meaning that it will remove an electron form almost anything. Therefore, it is amazingly reactive, and it even reacts with glass.
Manganese is not radioactive; chemically is sufficiently reactive.
Unstable isotopes can be chemically reactive.
yes it is
yes
Cesium of the normal metals but Francium is more so but there has only been a few grams found on the planet.
yes the most chemically reactive elements are in group 1