What isotope has 18 protons and 22 neutrons?

Argon.

Explanation:

Argon is the element having 18 protons and 22 neutrons present in its nucleus. so its atomic number is 18 and mass number is 40 if we added both number of protons and neurons. Argon belongs to noble family due to completion of outermost shell and non reactive nature. It is the third most abundant gas about 0.934% present on the earth after nitrogen and oxygen.

the correct answer is a

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.