| Introduction |  | | Mass of protons, neutrons and electrons is very small. A proton weighs 1.6726 x 10-27kgand mass of a neutron is 1.674 x 10-27 kg. A neutron therefore is slightly heavier than a proton. An electron weighs 9.1.93 x 10-31 kg. Thus the mass of an electron is about 1830 times smaller than a proton. Now you can imagine how small an atom is! |  | | The dimension of an atom is of the order of 10-10 m. This unit of measurement is called an Angstrom and is written as Ao. That is 10-10 m = 1 Ao. On a 1 cm marking on your ruler, you can place 10 crore Hydrogen atoms side by side! A nucleus of an atom is more compact and its approximate size is of the order of 10-15 m. This unit of measurement is called a Fermi and is written as fm. That is 10-15m = 1fm. It has to be noted here that both the nucleus as well as the atom is not a point like particle, but has a certain definite size or dimensions. | | Previous | Next |
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