Which of the following oxides is most amphoteric?

What is the correct order with respect to metallic property of $Zr, Cd, Sn, Sr$?

The correct order of the metallic nature of the following elements is

When $KI$ is passed through a solution containing $KCl, KF,$ and $KBr$,what happens?

Given below are two statements:
Statement $I$: Chlorine can easily combine with oxygen to form oxides,and the product has a tendency to explode.
Statement $II$: Chemical reactivity of an element can be determined by its reaction with oxygen and halogens.
In the light of the above statements,choose the correct answer from the options given below.

An atom with atomic number $20$ is most likely to combine chemically with the atom whose atomic number is