What is the main characteristic of the last elements in the periods of a periodic table? What is the general name of such elements ?

Explanation

The last elements of each period in the modern periodic table have their outermost shell complete. (8 electrons in the outermost orbit except Helium, which has only 2 electrons) Since the outermost orbit is full, these elements are generally inert and do not react with other thus called "Inert gases" or "Noble gases".