Thomson's Model of an Atom

Thomson proposed that an atom consists of a positively charged sphere with electrons embedded in it, similar to a Christmas pudding with electrons like currants.

Thomson described the positive charge as spread all over the atom like the red edible part of a watermelon, while the electrons are studded in the positively charged sphere, similar to seeds in a watermelon.

Thomson proposed that the negative and positive charges are equal in magnitude, making the atom as a whole electrically neutral.

<p>The results of experiments by other scientists could not be explained by Thomson's model because it failed to account for certain experimental observations.</p> Signup and view all the answers

<p>Ernest Rutherford designed an experiment to investigate how the electrons are arranged within an atom.</p> Signup and view all the answers

<p>Rutherford chose a gold foil because he wanted as thin a layer as possible to conduct his experiment.</p> Signup and view all the answers

<p>Most of the fast moving α-particles passed straight through the gold foil, some were deflected by small angles, and a small fraction rebounded.</p> Signup and view all the answers

<p>Rutherford concluded that most of the space inside the atom is empty, the positive charge occupies very little space, and the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.</p> Signup and view all the answers

<p>The features were: a positively charged nucleus at the atom's center, nearly all the mass residing in the nucleus, and electrons revolving around the nucleus in circular paths.</p> Signup and view all the answers

<p>The mass of the fast-moving α-particles was 4 u, and they had a considerable amount of energy.</p> Signup and view all the answers

<p>Rutherford calculated that the radius of the nucleus is about 105 times less than the radius of the atom.</p> Signup and view all the answers

<p>Rutherford's experiment revealed that most of the space inside the atom is empty, allowing for the passage of α-particles without deflection.</p> Signup and view all the answers

<p>Rutherford concluded that the positive charge of the atom occupies very little space.</p> Signup and view all the answers

<p>Christmas pudding or watermelon</p> Signup and view all the answers

<p>To understand the internal structure of the atom</p> Signup and view all the answers

<p>Alpha (α)-particles</p> Signup and view all the answers

<p>Gold foil, because he wanted as thin a layer as possible</p> Signup and view all the answers

<p>The positive charge is concentrated in a small, dense region called the nucleus</p> Signup and view all the answers

<p>The atom is mostly empty space with a small, dense nucleus</p> Signup and view all the answers

<p>4 u</p> Signup and view all the answers

<p>Most of the space inside the atom is empty.</p> Signup and view all the answers

<p>One out of every 12000 particles</p> Signup and view all the answers

<p>All the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.</p> Signup and view all the answers

<p>About 105 times less than the radius of the atom</p> Signup and view all the answers

<ol> <li>Positively charged nucleus at the center of an atom. 2. Nearly all the mass of an atom resides in the nucleus. 3. Electrons revolve around the nucleus in circular paths.</li> </ol> Signup and view all the answers

<p>All the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.</p> Signup and view all the answers

<p>To emphasize the unexpectedness of the results</p> Signup and view all the answers

<p>All the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.</p> Signup and view all the answers

<p>His work on the discovery of electrons</p> Signup and view all the answers