What are the Alkali metals?
Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Caesium (Cs), and Francium (Fr) They have one electron in the outermost shell ready for ionization. They lose that electron very easily to attain the stable state. (Have the least ionization potential) All these elements are highly reactive and are available only in their natural forms. They react vigorously with water to form hydroxides while releasing a lot of energy in the process. This energy shows in the form of heat, enough to ignite the hydrogen released.
Rubidium and Caesium are indicated as the King and Queen of Group I in this video. The anchor leaves saying "There is one more metal called Francium that can have a worser effect. But (thankfully) it is out of bounds to us" On the same scale that the anchor used, Francium must be God. 😉 Wonder, what Franicium's would be like?
Also, in the video, John describes Rubidium as grenade in the bathtub. But for Caesium, I could not get what was said. My friend Shankar couldn't either.