Can gas be made to block radiation better?
Your question seems to be about the ozone layer, but shows some misunderstanding. 

First, ozone, $\ce{O3}$, absorbs some "radiation", specifically electromagnetic radiation, e.g. visible light or ultraviolet light (UV), as do many other gases. This absorption is not the same for all wavelength ("colors"), but in the UV region peaks about 250 nm, which is a good thing for us, because plants and animals have not evolved good protection from that light, and the small amount of $\ce{O3}$ in the upper atmosphere is enough to block most of that UV. Sulfur dioxide, $\ce{SO2}$, released in volcanic eruptions, is also able to absorb 250 nm UV. Molecular oxygen, $\ce{O2}$, absorbs "vacuum UV", 10-100 nm, which otherwise would be a problem.

Second, Earth is continually bombarded by another type of "radiation", particles such as cosmic rays and solar energetic particles. Rather than electromagnetic energy, these are made of particulate matter such as protons or nitrogen nuclei. All gases, in fact all matter, help block these particles. Magnetic fields such as that of the Earth help divert them around the planet, too, but there is some question whether a magnetic field is essential to blocking particulate radiation. Here at the bottom of the atmosphere there is a column of air weighing about a kilogram over each square centimeter, which is sufficient to block primary cosmic rays, though a showers of weaker secondary particles do reach the surface. There is no advantage to a conductive Faraday cage to protect the Earth.

Third, all gases conduct electricity when ionized. The majority of air is nitrogen, oxygen and argon, which produce various colors in an aurora. Though magnificent to watch, aurorae are simply evidence of energetic particles trapped in a magnetic field, ionizing the upper atmosphere. This layer of the atmosphere is called the ionosphere, and is responsible for long-distance radio communication. It's height varies from day to night and with solar storms.