Question

It has been found that nuclides with 2, 8, 20, 50, 82 and 126 protons or neutrons are exceptionally stable. These numbers are referred to as the magic numbers and their existence has led us to:
A. The idea of periodicity in nuclear properties is similar to the periodicity of chemical elements in periodic tables.
B. The so called “liquid drop model of the nucleus”
C. He so-called “shell model of nucleus”
D. Have a convenient explanation of “nuclear fission”

Answer 1

Hint: We know that when the atom has completely filled shells, they tend to have a very stable configuration. Also, some of the atoms have more stability when they are half-filled also. This has led many exceptional cases in cases of periodic table.


Complete step by step answer:We have given nuclides with 2, 8, 20, 50, 82 and 126 protons or neutrons. Let us understand why they are known as magic numbers.
As we said above, when a nucleus has fully filled shells, they are said to be very stable. In case of 2, 8, 20, 50, 82 and 126 atoms they all have completely filled shells. That is why they are called the magic numbers. Here, when we look at them as protons the atoms are helium, oxygen, calcium, nickel, tin, lead and the hypothetical unbihexium.
Now let us look in to the option given for us:
(a) This option is wrong since the magic number has not led us into the conclusion that periodicity in nuclear properties is similar to periodicity of chemical elements in periodic table. As the chemical elements have periodicity as we can see the inert gases of the periodic table.
(b) The liquid drop model of nucleus is based on the surface tension, as it says the atomic nuclei in which the nucleons behave like the molecules in a drop of liquid. So, this has no relation towards magic numbers, hence this option is wrong.
(c) The magic number has led us into the shell model of nucleus since the completely filled shells and its stability all came from the magic number. Hence this option is correct.
(d) Magic number does not give any explanation for nuclear fission; therefore, this option is wrong.

Hence, option (c) is correct.


Note:The isotopes with the magic number have unusual stabilities. This means that transuranium elements could theoretically be created with extremely large nuclei and yet not be subjected to the extremely rapid radioactive decay normally associated with high atomic number.s