Question

$^{234}U$ has $92$ protons and $234$ nucleons total in its nucleus. It decays by emitting an alpha particle. After the decay it becomes

• A. $^{232}\,U$
• B. $^{232}\,Pa$
• C. $^{230}\,Th$
• D. $^{230}\,Ra$

Answer 1

Answer: (D)

$^{230}\,Ra$

Answer 2

Alpha particle has mass number $4$ and atomic number $2 .$ Therefore, after emission of an alpha particle. The mass number of the ${ }^{234} U$ will reduce by $4$ and after decay it becomes ${}^{230} Ra$