Which of the element pairs would be most reactive with one another?

Hydrogen is a very reactive gas, and the alkali metals are even more reactive. In fact, they are the most reactive metals and, along with the elements in group 17, are the most reactive of all elements. (hope this helped you)

Mgo2 is the oxidation state of manganese oxide

Green is technically every other color but green but the other wavelengths of the other colors get absorbed by the object and the wavelength of the color green gets reflected