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20 THE JAINA PHILOSOPHY the mass of an electron which turned out to be very very small indeed According to his estimate, the mass of an whole hydrogen atom is 1840 times the mass of an electron This indicates that the main portion of atomic mass is contained in its positively charged component.
Thomson was, however, very far from the truth concerning the uniform distribution of the positive charge through the body of the atom In 1911, Rutherford showed that almost the entire mass as well as the positive charge of the atoms is concentrated in an extremely small nucleus located in the very centre of the atom As the result of his famous expenments on the scattering of the so-called "alpha particles in their passage through matter, Rutherford came to the suprising conclusion that both, the incident alpha particle and the positively charged part of the atom, are thousands of times smaller than the atom itself Thus the originally widespread positive charge of Thomson's atom shrunk into a tiny atomic nucleus in the centre of the atom, while the electrons rotated outside Thus the picture of the atom began to look more like a miniature solar system-nucleus being the sun and electrons being the planets
The diameter of the atom is 100,000 times greater than the diameter of the nucleus while its volume is 500,000 billion times the volume of the nucleus The atomic nucleus contains 99 97 percent of the total atomic mass and the distance between the electrons exceeds their diameter by several thousand times The electric attraction forces between the nucleus and the electrons obey the mathematical law of inverse square ie the forces are inversely propor9 99 87% of the total mass of the solar system is concentrated in the sun
