The atomic number and name of the metal that can effectively shield against gamma rays or X-rays, similar to how lead shields against visible light waves, is Tungsten (symbol: W).
Tungsten has a high atomic number of 74, which means it has 74 protons in its nucleus. Elements with higher atomic numbers tend to be more effective at absorbing and attenuating high-energy radiation such as gamma rays and X-rays.
Tungsten is commonly used in various applications where radiation shielding is required, including medical imaging, industrial radiography, and nuclear facilities. Its high density and atomic number make it an excellent choice for blocking and absorbing gamma rays and X-rays, providing effective protection from these forms of electromagnetic radiation.