Nuclear fission is the process of dividing an unstable atomic nucleus into other, more stable nuclei. This process was discovered in 1939 by Otto Hahn (1879-1968) and Fritz Strassmann (1902-1980).
The nuclear fission of uranium is the best known, since it is the most used for the generation of energy through nuclear reactions.
The process basically consists of making a neutron hit the nucleus of an atom and it will split into two more stable nuclei and will release neutrons, which will also reach other atoms causing a reaction in jail.
Nuclear Fission and Nuclear Fusion
Nuclear fission is the splitting of the nuclei of atoms. For example, when hit by a neutron (n), the uranium atom (U) can break apart and generate atoms of barium (Ba) and krypton (Kr) and three more neutrons (n).
Uranium nuclear fission can release the energy of 8.107 kJ/g.
THE Nuclear fusion it is the opposite process to fission. Instead of splitting the nucleus of the atom, the nucleus of two or more atoms joins together.
The most common reaction is the union of two isotopes of the element hydrogen (H). tritium (1H3) and deuterium (1H2) join together forming a helium atom (2he4), a neutron (n) and releasing large amounts of energy.
This is a much more violent process. The energy released is about 3.108 kJ/g. From it comes the functioning of the most destructive bomb on the planet: the hydrogen bomb.
Furthermore, while it is possible to control nuclear fission, used in reactors in nuclear power plants, the same does not happen with nuclear fusion.
Applications of nuclear fission
Nuclear fission is used in the following activities:
- Medicine: Radioactivity results from nuclear fission. Thus, it is used in x-rays and tumor treatments.
- Production of energy: Nuclear fission is an alternative in the production of energy in a more efficient and clean way, as it does not emit gases. Nuclear reactors are able to control the violence of the fission process by slowing down the action of neutrons so that an explosion does not occur. This type of energy we call Nuclear energy.
- Atomic Bombs: Atomic bombs work as a result of nuclear fusion and fission processes and have a high destructive power. The nuclear fission reaction gave rise to the Manhattan Project, created for the purpose of building nuclear weapons.
However, despite its advantages and applications, the energy produced in nuclear power plants gives rise to nuclear waste.
Thus, the main damage from the application of fission is the risk of an accident due to the use of radioactive material. Contact with these residues can lead to the emergence of various diseases, such as cancer and even death.
This situation can be exemplified by Chernobyl accident, which took place on April 26, 1986. It is considered the most serious in the history of commercial nuclear energy, causing a huge release of nuclear waste.
Also know about the Hiroshima Bomb.
nuclear fission process
The process occurs as a result of the incidence of the neutron on the atomic nucleus. When you accelerated bombardment of the atom that has a fissionable nucleus, it splits in two.
With this, two new nuclei appear and up to 3 neutrons and a large amount of energy are released.
The released neutrons can reach other nuclei and give rise to new neutrons. Thus, a Chain reaction, that is, a continuous process that releases a large amount of nuclear energy.
Uranium nuclear fission
The best known nuclear fission reaction is the one that occurs with uranium. When one neutron with enough energy it reaches the uranium nucleus, releasing neutrons that can cause the fission of other nuclei. This reaction is also known to release large amounts of energy.
From uranium (U) several products can be formed, such as barium (Ba), krypton (Kr), bromine (Br), lanthanum (La), tin (Sn), molybdenum (Mo), iodine (I) and yttrium (Y).
Exercises on nuclear fission
question 1
(Ufal) The equation:
represents a reaction of:
a) catalytic conversion.
b) radioactive decay.
c) redox.
d) nuclear fission.
e) nuclear fusion.
Correct alternative: d) nuclear fission.
When a neutron (n) hits an unstable atomic nucleus, such as uranium (U), there is a disruption and release of more stable atomic nuclei. The neutrons also produced in this reaction will reach other nuclei causing a chain reaction to occur.
question 2
What is the difference between fission and nuclear fusion?
Answer: While in nuclear fission there is a division of an atomic nucleus, in fusion the atomic nuclei unite.
question 3
(Ufal) Nuclear Fission is the division of a heavy and unstable atomic nucleus that occurs, for example, by bombarding this nucleus with neutrons, releasing energy. The alternative that correctly represents a nuclear fission equation is:
The)
B)
ç)
d)
Correct alternative: d) .
The mass number of an element corresponds to the sum of protons and neutrons. In the first member of the equation we have 92 protons in the uranium atom, which corresponds to the atomic number, and 143 neutrons, calculated by subtracting the number of protons from the mass.
Z = p = 92
A = p + n = 235
n = A - p = 235 - 92 = 143
In addition to the uranium neutrons, we have one more neutron that bombed the atomic nucleus and a total of 144 neutrons in the first member.
In the second member of the equation, the sum of the atomic numbers of barium (Ba) and krypton (Kr) totals 92 protons.
56 + 36 = 92
The neutron number of barium (Ba) is 84 and krypton (Kr) is 57. We obtain these values by subtracting the number of protons from the mass.
A = p + n = 140
n = A - p = 140 - 56 = 84
A = p + n = 93
n = A - p = 93 - 36 = 57
In the member being then we have 144 neutrons, as we add the neutrons from the two atomic nuclei with the three released in the reaction.
84 + 57 + 3 = 144
Therefore, the equation is correct: 92 protons and 144 neutrons in each member of the equation.
See university entrance exam questions on the topic in the list we have prepared: radioactivity exercises.
