The element used to block out dangerous radiation depends on the type of radiation.

Here's a breakdown:

For Alpha Radiation:

* Paper, clothing, or a thin layer of air can be sufficient to stop alpha particles.

For Beta Radiation:

* Aluminum, plastic, or a thicker layer of air are effective at stopping beta particles.

For Gamma Radiation:

* Lead, concrete, or a thick layer of water are needed to significantly attenuate gamma rays.

For Neutrons:

* Water, concrete, polyethylene, or boron are effective at slowing down and capturing neutrons.

It's important to note that:

* No material can completely block all radiation.

* The thickness and type of material needed to adequately shield from radiation depends on the energy of the radiation and the desired level of protection.

For specific applications, consult with radiation safety professionals for accurate shielding recommendations.