Respuesta :

critesmonica595

Mass of barium is 137.327 g/mol. Mass of radium is 226 g/mol.

Hence, radium has more mass therefore it will have the greatest density at STP.

Hope this helps :)

ujalakhan18

Answer:

Ra

Explanation:

Since density is directly proportional to mass and

Density=Mass/Volume

Atomic masses of Ba=137, Be=4, Mg=24, Ra=226

Hence Ra (radium) has the most density