Rutherford Atom Model: Did He Know Structure of Alpha Particles?

[SciencePF]

Did Rutherford knew the structure of alpha particles?

If so, why was so important the scattering of alpha particles in the gold foil experiment?

He knew the structure of helium atom!

What is wrong with me?

Thanks for your friendly collaboration and excuse me if the post makes no sense.

 

[Bob S]

The Wilson cloud chamber was developed in the 1890s. The famous Rutherford scattering of alpha particles was done 1n 1909. At this time, alpha particles were known to make ZnS (zinc sulphide) foils scintillate. He used a purified radium source for the alphas, and scattered them off a gold foil. What he did not expect was to observe essentially Coulomb scattering from a point (actually two, counting the alpha), rather than a plum pudding. Rutherford developed the theory of Coulomb scattering from point charges. Read below from Wiki

In physics, Rutherford scattering is a phenomenon that was explained by Ernest Rutherford in 1909, and led to the development of the Rutherford model (planetary model) of the atom, and eventually to the Bohr model.

The discovery was made by Hans Geiger and Ernest Marsden in 1909 when they performed the gold foil experiment under the direction of Rutherford, in which they fired a beam of alpha particles (helium nuclei) at layers of gold leaf only a few atoms thick. At the time of the experiment, the atom was thought to be analogous to a plum pudding (as proposed by J.J. Thomson), with the negative charges (the plums) found throughout a positive sphere (the pudding). If the plum-pudding model were correct, the positive “pudding”, being more spread out than in the current model of a concentrated nucleus, would not be able to exert such large coulombic forces, and the alpha particles should only be deflected by small angles as they pass through.

However, the intriguing results showed that around 1 in 8000 alpha particles were deflected by very large angles (over 90°), while the rest passed straight through with no deflection. From this, Rutherford concluded that the majority of the mass was concentrated in a minute, positively charged region (the nucleus) surrounded by electrons. When a (positive) alpha particle approached sufficiently close to the nucleus, it was repelled strongly enough to rebound at high angles. The small size of the nucleus explained the small number of alpha particles that were repelled in this way. Rutherford showed that the size of the nucleus was less than about 10−14 m.

 

[charng]

I can assure you that your post does make sense and I am happy to provide a response to your questions.

To answer your first question, yes, Ernest Rutherford did have knowledge of the structure of alpha particles. He discovered that they were actually the nuclei of helium atoms, which was a groundbreaking discovery in the field of atomic structure.

The importance of the scattering of alpha particles in the gold foil experiment lies in the fact that it provided evidence for Rutherford's atomic model. The experiment showed that most of the alpha particles passed straight through the gold foil, but a small percentage were deflected at large angles. This indicated that the majority of the atom was empty space, with a small, dense nucleus at the center. This was a significant finding that challenged the previous model of the atom, which proposed a uniform distribution of positive charge throughout the atom.

As for your final question, there is nothing wrong with you. It is important to ask questions and seek knowledge, and I am happy to provide answers and clarification. Collaboration and open-mindedness are crucial in the scientific community, and I appreciate your friendly approach to seeking information. Keep asking questions and never stop learning!

 

[charng]

I would like to clarify that Rutherford did not know the exact structure of alpha particles when he proposed his atom model. However, he did know that alpha particles were made up of two protons and two neutrons, which is the same structure as a helium atom. This information was crucial in his gold foil experiment, as it allowed him to understand the behavior of the alpha particles as they passed through the foil. The unexpected results of the experiment, where some alpha particles were deflected at large angles, led Rutherford to propose the nuclear model of the atom, where the majority of the atom's mass is concentrated in a small, dense nucleus. This was a groundbreaking discovery that revolutionized our understanding of atomic structure. So, while Rutherford did not know the exact structure of alpha particles, his understanding of their composition was essential in his groundbreaking experiment and subsequent model of the atom. As for your question about what is wrong with you, I am not qualified to answer that and it is not relevant to the discussion at hand. Thank you for your collaboration and let's continue to work together to advance our understanding of science.