proton charge radius from electron scattering

The total number of nucleons is termed as mass number. Nucleons (proton and neutron) are much heavier than an electron indicating that mass of atomlies in its nucleus. The nucleus consists of protons and neutrons called nucleons. If cricket ball is nucleus then radius of atom will be about 5 km.Īn atom consists of tiny positively charged centre called nucleus. The radius of nucleus (10–13 cm) is about 1/100,000 of that atom (10–8 cm). The volume of nucleus is very small as compared to total volume of atom. If cricket ball is nucleus then radius of atom will be about 5 km. The radius of nucleus (10 –13 cm) is about 1/100,000 of that atom (10 –8 cm). This very small portion of the atom was called nucleus. The positive charge has to be concentrated in a very small volume that repelled and deflected few positively charged a-particles. Most of space in atom is empty because most of a-particles passed through the foil. Rutherford's Conclusions regarding Model of Atom: Most of a -particles passed through the gold foil undeflected.Ī small fraction of a-particles was deflected by small angles.Ī very few a-particles (1 in 2000) bounded back, i.e., were deflected by nearly 180°. Whenever an a-particle struck the screen, a tiny flash of light was produced at that point. The thin gold foil had a circular flurescent ZnS screen around it. Rutherford bombarded high energy a-particles from radioactive source on thin foil (thickness 10 –7m) of gold metal.

Rutherford's a-Scattering Experiment (Discovery of Nucleus)

They are positively charged (+2) helium ions having high energy emitted during radio-active decay of unstable elements like Uranium. This model of atom could account for the electrical neutrality of atom, but it could not explain the results of gold foil experiment carried out by Rutherford. This model is also called the ‘raising pudding’ model. In this model the atom is visualized as a pudding or cake of positive charge with raisins (electrons) embedded into it. Thomson proposed a model in which atom was assumed to be uniform sphere with radius 10 cm of positive electricity (positive charge) with electrons embedded into it in such a way as to give the most stable electrostatic arrangement. Chemistry Formula for class 11 chapter- Atomic Structure

Proton charge radius from electron scattering