Answer:
d)krypton.
Step-by-step explanation:
Noble gases are a group of elements in the periodic table that have full outer electron shells, making them stable and unreactive. They are characterized by their low reactivity and tendency to exist as single atoms rather than forming compounds with other elements.
Krypton is a noble gas and is represented by the symbol Kr in the periodic table. It is located in Group 18, also known as Group 0 or the noble gases group. Other elements in this group include helium (He), neon (Ne), argon (Ar), xenon (Xe), and radon (Rn).
Noble gases are widely used in various applications, such as in lighting (neon signs), cryogenics (helium for cooling superconducting magnets), and as inert gases in welding and other industrial processes. Due to their stable nature, noble gases have limited chemical reactions, making them valuable in specific industries and scientific research.