Question

which of the above elements is most reactive and why?​

Answer 1

Answer:

Among the four elements mention in the question,the potassium is the most reactive element. Similarly, the the distance between the nucleus of an atom and the outermost shell of electron is also an important factor behind the reactivity of an element.

Answer 2

In chemistry, an element is a pure substance consisting only of atoms that all have the same numbers of protons in their atomic nuclei. Unlike chemical compounds, chemical elements cannot be broken down into simpler substances by chemical means..