Answer:
argon and helium
Explanation:
Argon and Helium is belongs to noble gas. Since novel gases are completely filled outer orbital. therefore they are erratic nature. Hence, noble gas are very stable as it neither except electron nor it denote due to it paired of electronic configuration.
Depending on the materials being welded, these atmospheric gases react with welding area and either it reduces the quality of the weld or make the welding more difficult.
Therefore, to protect welding area from atmospheric gases noble gases which are small in size are used.
Thus, argon and helium are used.
Carbon Dioxide is formed when two oxygen atoms chemically combine with a carbon atom. The term that will best describe carbon dioxide is a compound. That will make the correct answer D.
Atomic mass is the mass of a chemical element expressed in atomic mass units. Molar mass the mass of a given substance divided by its amount of substance in (mol) .
