Rutherford was one of the early scientists who worked on the atomic model. Before his discovery of the nucleus, the widely accepted theory was J.J Thomson's Plum Pudding Model. In this model, all the protons, electrons and neutrons are in the nucleus. But the electrons are more in number such that the electrons act as the 'pudding' and the proton and nucleus the 'plum'. This was Rutherford's hypothesis in his gold foil experiment. In order to test the Plum Pudding model, he hypothesized that when a beam of light is aimed at the atom, it would not diffract because the charges in the nucleus are well-distributed. However, his experiment disproved Thomson's model. Some light indeed passed through but a few was diffracted back to the source. He concluded that this was because there is a dense mass inside the atom called nucleus. Thus, from there on, he proposed the model that the electrons are orbiting around the nucleus.
(Na2Cr2O7) all the numbers are bellow not over
Answer: AZ is the insoluble choice.
Explanation:
Z is an anion of a weak electronegative element. Hence, it bounds lightly with the highly electropositive cation A to form AZ.
AZ is not as ionic as AX, AY, BX, BY and BZ, so it is insoluble in water and yields precipitate on reaction with the salt of a weaker metal.
