Physics · nuclei · NEET
No. In gamma decay only energy is emitted, not any particle with charge or mass number. So Z stays the same and A stays the same. The nucleus is the SAME element before and after — it just moves from a higher energy level to a lower one. Written form: X* (excited) turns into X (ground) plus a gamma photon. The star mark means excited state.
A gamma photon has zero rest mass and zero charge. It only carries energy and momentum. Because no proton or neutron leaves the nucleus, the count of nucleons (A) is unchanged and the count of protons (Z) is unchanged. The tiny mass equal to the released energy (E = mc squared) is the difference between the excited and ground state, but we still call it the same nuclide.
Just like an atom can have electrons in higher energy levels, a NUCLEUS has its own energy levels. After an alpha or beta decay, the daughter nucleus is often left in an excited (high-energy) state, not the lowest state. This high-energy nucleus is written with a star, for example Ni-60*. It quickly drops to the ground state and the extra energy comes out as one or more gamma photons.
From the NUCLEUS. Gamma rays in gamma decay are emitted when protons and neutrons rearrange from a higher nuclear energy level to a lower one. This is different from X-rays or visible light, which come from ELECTRONS jumping between atomic energy levels. Nuclear energy gaps are in MeV (millions of eV), so gamma photons carry far more energy than light or X-rays.
Keep Z and A the same on both sides and add a gamma photon. Example: after beta-minus decay, Cobalt-60 gives excited Nickel-60*. Then Ni-60* (Z=28, A=60) turns into Ni-60 (Z=28, A=60) plus gamma. The photon energy equals the energy difference between the two nuclear levels, for example E(gamma) = E(upper) minus E(lower).
Alpha and beta decay change the nucleus into a daughter that is usually NOT in its lowest energy state. This leftover excited daughter then de-excites by emitting a gamma photon. That is why gamma rays are usually seen together with alpha or beta decay, rarely completely alone.
It is when an excited nucleus (one with extra energy) drops to a lower energy state and gives out that extra energy as a gamma ray photon. The element does not change.
No. Because Z (protons) and A (nucleons) both stay the same, the nucleus remains the same element. Only its internal energy decreases.
The gamma photon energy equals the gap between the two nuclear energy levels, usually in the range of about 0.1 MeV to a few MeV — much larger than visible light or X-ray photons.
Gamma rays are the high-energy photons themselves. Gamma decay is the PROCESS in which an excited nucleus emits such a photon to reach a lower energy level.
Yes. Protons and neutrons in a nucleus can occupy discrete nuclear energy levels. A jump from a higher to a lower nuclear level releases a gamma photon, just as electron jumps release visible or X-ray photons.
Gamma photons have no charge and no rest mass and carry high energy, so they interact weakly with matter and pass through much more material than alpha or beta particles.
