General Properties of Nucleus

General Properties of Nucleus:

(1) Atomic Number (Z)- It represents the total number of protons inside the nucleus.

(2) Mass Number (A)- It represents the total number of protons and neutrons inside the nucleus.

(3) Nuclear Mass- It is expressed in terms of atomic mass unit (amu). One amu is defined as 1/12th mass of C12 i.e. there are 6.025 x 1026 atoms in 1 kg mole (or 12 kg) of carbon.

amu formula - General Properties of Nucleus

(4) Nuclear Charge- The charge of the nucleus is positive due to protons contained in it.

Charge of proton = 1.6 x 10-19 C

(5) Nuclear Size- Nuclear radius is of the order of 10-15 m. According to the semi-empirical formula, the nuclear radius is given by-

R = R0 A1/3
Where R0 is the constant with an average value of 1.4 x 10-15 m.

(6) Nuclear Shape- In order to provide the least surface area, the nucleus is always spherical in shape.

(7) Nuclear Density-

Nuclear Density - General Properties of Nucleus

(8) Nuclear Spin and Quantum States-Similar to electrons, nucleons also possess a spin. Also, there are sets of quantum states and a corresponding number of discrete energy levels with nucleons. Transitions between different nuclear states are accompanied by the emission of γ-rays.

(9) Nuclear Stability- Nuclear stability means that the nucleus of an element is stable and thus it does not decay spontaneously emitting any kind of radioactivity.

Factors affecting nuclear stability are-

(i) Number of Protons and Neutrons- If the N/Z ratio is one, nuclei are more stable and if N/Z > 1.5, nuclei are unstable.

Also for an even number of protons and neutrons, nuclei are in general stable than those having an odd number of them.

(ii) Binding Energy- Intermediate elements with comparatively large binding energy per nucleon are more stable than lighter and heavier elements.

(iii) Nuclear Forces- According to Yukawa Meson’s theory, nuclear forces arise due to the rapid exchange of π-mesons (π+, π0 and π) between protons and neutrons.

Nuclear forces are short-range, attractive forces which are strongest in nature for P-P, P-N and N-N interactions. These forces are independent of charge.

Depression in Freezing PointCoulomb’s Law
Osmosis and Osmotic PressureKirchhoff’s Laws
Experimental Measurement of Osmotic PressureFaraday’s Laws of Electromagnetic Induction
Relative Lowering in Vapour PressureForce and Motion– Tamil Board

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