Which of the following radioactive decay types can result in a transition to a lower energy state without particle emission?

The correct answer is the isomeric transition, which involves the nuclear system moving from a higher energy state to a lower energy state without the emission of particles. This process is part of radioactive decay but is distinct because it does not involve the release of alpha or beta particles or any other matter. Instead, it typically occurs by the release of gamma rays to shed excess energy from the nucleus, resulting in a more stable lower energy configuration.

In the context of other decay types, alpha and beta decay involve the emission of particles. Alpha decay releases a helium nucleus (alpha particle), while beta decay involves the conversion of a neutron into a proton (or vice versa) with the emission of an electron or positron. Electron capture is another decay mode where an electron is captured by the nucleus, but it also results in the emission of neutrinos and is fundamentally different from an isomeric transition since it changes the composition of the nucleus rather than merely transitioning to a lower energy state.

Thus, isomeric transition is unique among these processes because it strictly refers to the transition within the nucleus without particle emission, highlighting the importance of internal energy states in nuclear physics.