What isotope of radium is converted into radon-222 by emission?

Radium-226 is the isotope of radium that is converted into radon-222 through alpha decay. During this process, radium-226 emits an alpha particle and transforms into radon-222, which is a radioactive gas. This decay is part of the uranium-238 decay series. Radon-222 is known for its health risks due to its radioactive properties.