The abbreviation is more correctly described as the 'CHEMICAL SYMBOL'. It is 'Ar'.
Argon is used in welding as a shielding gas to protect the weld area from atmospheric gases such as oxygen and nitrogen. It helps prevent oxidation and enhances the quality of the weld by creating a stable arc and reducing spatter. Additionally, argon is chemically inert, which makes it suitable for a wide range of welding applications.
Argon is a noble gas. There are no covalent bonds
The use of the word "weakness" is purely subjective. Something that may be considered a weakness in some circumstances may be regarded as a strength in others. For example, argon is inert and so does not form compounds. A weakness? But that same property makes it extremely useful for the storage of highly reactive elements. A strength!
Argon comprises almost 1% of the air. It is obtained by fractional distillation of liquid air.
Helium accounts for around 8% of the volume of all matter (baryonic particles) in the universe.
It is very inert. However, under extreme conditions it can be made to react - to form compounds. Argon hydride was detected in the Crab Nebula in 2010.