Why do non metals tend to gain electrons to form negitive ions

Ionic bonds form only between metals and nonmetals. That's because metals “want” to give up electrons, and nonmetals “want” to gain electrons. It takes energy to remove valence electrons from an atom and form a positive ion. Energy is released when an atom gains valence electrons and forms a negative ion

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.