1. Some dates, namely years are mentioned in the text. Match them with the events described.
| J. Chadwick discovered the neutron at Cambridge. | |
| Fermi and his colleagues bombarded elements with neutrons and discovered that nuclear bombardment caused nuclear transformation. | |
| The Joliot-Curies discovered the transmutation of aluminium into the isotope of phosphorus. | |
| Leo Szilard assigned the patent to the British Admiralty to help keep it secret. | |
| E. Rutherford published his results on the bombardment of nitrogen atoms by alpha particles. | |
| N. Bohr improved Rutherford’s model using quantum mechanics in the description of orbiting electrons behaviour. | |
| E. Rutherford mentioned in his lecture that there might be another constituent in the atomic nucleus. |
2. Choose the best ending a, b, or c to complete the sentences.
1. Neils Bohr
a) created a new model for describing the behaviour of the nucleus.
b) used his model for explaining processes taking place at the atomic and sub-atomic level.
c) improved Rutherford’s model using quantum mechanics.
2. Neils Bohr
a) supposed that electrons revolved around the nucleus in circular and elliptical orbits.
b) thought that electrons rotated around the nucleus in elliptical orbits.
c) assumed that electrons did not orbit the nucleus.
3. Ernest Rutherford
a) bombarded nitrogen atoms by beta particles and created a new atom.
b) managed to realize the world’s first artificial nuclear reaction.
c) used alpha and beta particles to cause artificial transmutation of elements.
4. Rutherford’s achievement
a) remained unnoticed.
b) disappointed the public.
c) astonished the world.
5. One more constituent of the nucleus, the neutron was discovered by
a) Irene Joliot-Curie.
b) James Chadwick.
c) Ernest Rutherford.
6. The neutron
a) has a negative charge.
b) is more powerful than the proton and could split even the heaviest elements.
c) can split only light elements.
7. The cyclotron
a) was more complex than a linear accelerator.
b) was designed to produce energy.
c) was used to speed particles.
8. The Joliot-Curies
a) managed to transmute aluminium into radioactive phosphorus.
b) bombarded aluminium and transmuted it into its isotope.
c) were the last to obtain radioactive material
9. Fermi and his colleagues.
a) detected fast .neutrons.
b) showed by their experiments that electrons had different energy levels.
c) discovered that neutron bombardment resulted in nuclear transformation in nearly every element.
3. Give answers to the following questions.
1. How did Neils Bohr modify Ernest Rutherford’s atomic model?
2. What experiments did Ernest Rutherford make in 1919 and what did he create?
3. how did the world react to Rutherford’s discovery? Why?
4. What can the bombardment of atoms by particles result in?
5. Who discovered the neutron?
6. What is the neutron?
7. What device was designed by an American physicist E. Lawrence? For what purpose was it used?
8. What discovery did the Joliot-Curies make in 1933?
9. What was Fermi’s breakthrough?
10. Why was Fermi’s work an important step in the development of nuclear fission?
4. Some of the sentences given below contain factual mistakes. Find and correct them.
1. Bohr deduced that electrons moved in circular orbits.
2. The atomic number of any element is connected with the charge of the electron.
3. Rutherford’s discovery of 1919 meant that the dream of scientists was realized..
4. Rutherford thought that the neutron was the sole constituent of the atomic nucleus.
5. Irene Joliot-Curie identified penetrating particles as neutrons when she bombarded beryllium with alpha rays.
6. The Joliot-Curies transmuted aluminium into its radioactive isotope.
7. Enrico Fermi was a talented theoretician.
8. Fermi thought that neutrons had different energy levels.
9. Uranium-239 was the first man-made element.
5. Arrange the sentences below in the logical order to sum up the contents of the text.
1. The neutron is more powerful than the proton as it can split nuclei of the heaviest elements.
2. Fermi’s work was another important step in the development of nuclear fission.
3. Neils Bohr modified Rutherford’s atomic model.
4. Ernest O. Lawrence designed a new tool, the cyclotron.
5. Enrico Fermi wrote a theoretical treatise on beta decay.
6. James Chadwick discovered the neutron.
7. The Joliot-Curies transmuted aluminium into the isotope of phosphorus.
8. Rutherford realized the world’s first artificially induced nuclear reaction in 1919.
9. Leo Szilard attempted to generate a chain reaction in his laboratory.
10. The Joliot-Curies obtained the world’s first artificial radioactive material.
11. Fermi discovered that neutron bombardment caused nuclear transformation in nearly every element.