The element on the periodic table represented by the symbol 'Ar' is Argon. Argon is a noble gas and is colorless, odorless, and inert under most conditions, which means it does not readily react with other elements. It is the third most abundant gas in the Earth's atmosphere, making up about 0.93% of the atmosphere by volume. Argon is commonly used in various applications, such as providing inert environments for welding, producing incandescent and fluorescent lighting, and as a protective atmosphere for sensitive chemical processes. Its non-reactive nature makes it highly valuable in technology and industry.