Different versions of the same element, like pictured below, add known as _ The number 12,13 and 14 refer to the _

→ Are known as isotopes.

→ 12, 13 and 14 are mass numbers

Explanation:

Isotopes are atoms of the same element with same atomic number but different mass numbers.

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.