Mass Defect and Binding Energy Notes : Nuclear Binding Energy
The rest mass of the stable nucleus of a stable atom is always less than the sum of the masses of constituent nucleons. The difference is called the mass defect Δm (i.e., Δm.c2) is utilised in keeping the nucleons bound together. This energy is known as the binding energy. In order to break the nucleus into its constituent nucleons an amount of energy equal to its binding energy has to be supplied to the nucleus. The mass defect per nucleon Δm/A = P, is called the packing fraction of the nucleus.
Mass Defect of Helium Nucleus Notes | Nuclear Binding Energy
Atomic mass is the mass of a single atomic particle or molecule. It is the sum of protons and electrons present in the atom of an element. It is expressed in mole. It is simply a collection of nuclides that make up a chemical element. it is a whole number.
Atomic weight is the ratio of atom of an element. The average weight of an atom is relative to the 1/12 weight of the carbon -12 atom. It is also referred to as relative atomic mass.The value is not necessarily a whole number.
The nucleons are bound together in a nucleus and the energy has to be supplied in order to break apart the constituents into free nucleons. The energy with which nucleons are bounded together in a nucleus is called as Binding Energy (B.E.). In order to free nucleons from a bounded nucleus this much of energy (= B.E.) is to be supplied.
It is observed that the mass of a nucleus is always less than the mass of constituent (free) nucleons. This difference in mass is called as mass defect and is denoted as Dm.
The mass defect per nucleon is called packing fraction of the nucleus.
In order to break the nucleus into its constituent nucleons an amount of energy equal to this binding energy has to be supplied to the nucleus.
Rest mass of the stable nucleus of a stable atom is always less than the sum of the masses of constituent nucleons.
When a heavy nucleus splits into two lighter nuclei, energy can be released and the process is known as nuclear fission.
When two lighter nuclei combine to form a heavier nucleus, energy can be released and the process is known as nuclear fusion.
Question 1:-
Which of the following statements is incorrect?
(a) Mass defect is the amount of matter that would be converted into energy if a nucleus were formed from initially separated protons and neutrons.
(b) Nuclear binding energy is the energy released in the formation of an atom from subatomic particles.
(c) Mass number is the sum of all protons and electrons in an atom.
(d) Nuclei with highest binding energies are the most stable nuclei.
Question 2:-
Which isotope below has the highest nuclear binding energy per gram? No calculation is necessary.
(a) 4He
(b) 16O
(c) 32S
(d) 55Mn
Question 3:-
Which of the following describes what occurs in the fission process?
(a) A heavy nucleus is fragmented into lighter ones.
(b) A neutron is split into a neutron and proton.
(c) Two light nuclei are combined into a heavier one.
(d) A proton is split into three quarks.
Question 4:-
Two isotopes of an element have
(a) the same number of nucleons in their nuclei.
(b) the same number of protons as well as neutrons.
(c) the same number of protons but a different number of neutrons.
(d) a different number of protons but the same number of neutrons.
Question 5:-
The chemical properties of an atom (what element it is) are determined by
(a) its atomic number.
(b) its mass number.
(c) its neutron number.
(d) All of these are correct.
