B. ATOMS OF THE SAME ELEMENT THAT HAVE A DIFFERENT NUMBER OF NUETRONS
Explanation:
Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
).
is present at the intermediate position in electrochemical series with a standard reduction potential of 0 V (
).
whereas
is reduced to
and gaseous