Question

An isotope undergoes radioactive decay by emitting radiation that has no mass. What other characteristic does the radiation have?
some shielding required
positive or negative charge
low penetrating power
no charge

Answer 1

No charge.

Massless radiation from radioactive decay is gamma radiation (photons). Photons have no rest mass and carry no electric charge (they are highly penetrating, so they require dense shielding like lead or concrete).