Isotopes of an element have the same number of protons but different numbers of what? I have no idea what subject to put this under qwq

Isotopes is a phenomenon whereby atoms of the same element exhibit different mass numbers but have the same atomic number.I hope this helps... Thank you for the question

the answer is the

the electrical  conductivity  of asolution  of an electrolyte is measured by determining the resistance of thesolution  between two flat or cylindrical electrodes separated by a fixed distance.