Knowing more on Alpha Decay Equation

In alpha decay, the nucleus of an element gets dissociated into other elements along with the release of alpha particles and a high amount of energy. The formula for the alpha particle is ⁴He2.  Generally, elements that are heavier than lead and have lighter nuclei of lanthanide elements undergo the process of Alpha decay. Based on structural analysis, the alpha particle is similar to the helium ion, denoted by the Greek letter α. Generally, the atoms with an atomic number greater than 81 emit the alpha particles. One of the examples of alpha decay is the alpha decay of U-238, which produces Th‐234 with one alpha particle. It was found that the alpha, beta, and gamma decay equations are all radioactive reactions.

Radioactive Decay

The decomposition of a nucleus of a heavy atom into smaller ones is known as radioactive decay. In this decomposition, an excess amount of energy is released. There are three types of radioactive decay as mentioned below:

1. Alpha decay: In Alpha decay, one helium ion is released. The formula for an alpha particle is ⁴He2.
2. Beta decay: In beta decay, one electron is released.
3. Gamma decay: In gamma decay, high-energy photons are emitted.

Alpha Particle

The formula for the alpha particle (⁴He2+) makes it clear that it has 2 protons and 2 neutrons only, and zero electrons. The alpha particle carries a +2 charge. 

Alpha Decay

If any radioactive element disintegrates into another element then it emits an alpha particle and the mass and the atomic number of that element will decrease by 4 units and 2 units respectively. Hence, that element will convert into another element with the effect of a change in atomic number. The formula for the alpha particle is ⁴He2. An example of alpha decay is Americium-241 decay. In this radioactive decay, ²⁴¹Am converts into ²³⁷Np, resulting in the emission of alpha particles. The equation of this radioactive decay is given below:

²⁴¹Am95 → ²³⁷Np93 +⁴He2 +5.638 MeV

 In the above equation, ⁴He2 resembles the formula of alpha particles.

Alpha Decay of U-238

In this process, the disintegration of the nucleus of Uranium-238 decays into thorium-234 with the emission of one Alpha particle. The equation of this radioactive disintegration of U-238 is as given below:

²³⁸U92 → ²³⁴Th90 + ⁴He2

In the above equation, ⁴He2 resembles the formula of alpha particles.

Beta Decay

In beta decay, there is a spontaneous emission of an electron (beta minus) or a positron (beta plus) from the nucleus. 

There are two types of beta decay:

• Beta minus decay. 

• Beta plus decay.

A common example of beta minus decay is given below: 

³²P15 → ³²S16 + e– +v

One of the common examples of beta plus decay is shown below:

²²Na → ²² Ne + e+ + v 

These radioactive decays are controlled by the above equations. So, no one can predict which nucleus will go into the decomposition. But the radioactive decay can be characterised by a half-life. An antineutrino is emitted along with the emission of an electron in beta minus decay. On the other hand, a neutrino will be emitted in beta plus decay. These electrons are negatively charged but the neutrino is neutral in polarity with a small mass. 

Their interactions with other atoms are weak. The change in mass number gets unaffected in both beta plus and beta minus decay. In beta minus decay due to the emission of one electron, the atomic number increases by 1 while in beta plus decay due to the emission of one positron, the atomic number decreases by 1. A free neutron can be decayed into a proton, but a proton can be decayed into a neutron only inside a nucleus. 

Events for beta plus decay: In the beta plus decay, a proton converts into a neutron.

P → n + e+ + v

Events for beta minus decay: In beta minus decay, a neutron is converted into a proton, electron, and antineutrino.

n → p + e– + v– 

Gamma Decay

Similar to the atomic energy levels, a nucleus has different energy levels in which the basic one is the ground state and the higher ones are excited states. Each spacing of atomic energy level is of the order of eV, while the difference in nuclear energy levels is of the order of MeV.

In gamma decay, a photon is emitted due to the difference in the energy of the nucleus as it gets decayed to the ground state from the excited state spontaneously. This is called gamma decay. This is a common example of successive emission of gamma rays where the nucleus of excited states gets to the ground states with the formation of two gamma rays with energies of order 1.17 MeV and 1.33 MeV from β decay.

Conclusion

All elements that occur in nature are radioactive. Every element has its properties with a specific atomic configuration. Some of the elements have a heavier nucleus, showing radioactive decay through alpha, beta or gamma decay. Alpha particle is positively charged, a beta particle is a form of electrons and the gamma particle is an electromagnetic wave. In Alpha decay, the nucleus of an element gets dissociated into other elements with the release of alpha particles and a high amount of energy. The formula for the alpha particle is ⁴He2.