The flow of helium nuclei;
Neutron flux.
What kind of radiation is a threat during nuclear explosion?
92 U 238 ?
92; 2) 238; 3) 146; 4) 52.
Polonium isotope nucleus 84 Po 208 emits an alpha particle. What element is formed?
84 Po 208 ; 2) 8 5 At 208 ; 3) 8 2 Pb 20 4 ; 4) 8 0 Hg 20 0 .
Strontium nucleus 38 Sr 90 has undergone beta decay. Determine the number of neutrons in the newly formed nucleus. What is this element? ___________________________
Neptunium isotope nucleus 93 Np 237 83 Po 213 ... Determine the number of α-decays. _________________
For 16 hours, the activity of the radioactive element decreased by 4 times. What is the half-life?________________________
34 Se 79 ? _ ___________________
Option 2.
Which scientist discovered the radioactive element polonium?
Boron; 2) Rutherford; 3) Becquerel; 4) Warehouse-Curie.
What is gamma radiation?
The flow of electrons of different speeds;
The flow of helium nuclei;
Stream of high energy photons;
Neutron flux.
What radiation has the greatest penetrating power?
α; 2) β; 3) γ; 4) neutron radiation.
How many nucleons are in the uranium nucleus 92 U 238 ?
92; 2) 238; 3) 146; 4) 52.
Polonium isotope nucleus 84 Po 208 emits 2 alpha particles. What element is formed?
84 Po 208 ; 2) 8 5 At 208 ; 3) 8 2 Pb 20 4 ; 4) 8 0 Hg 20 0 .
Strontium nucleus 38 Sr 90 has undergone alpha decay. Determine the number of neutrons in the newly formed nucleus. What is this element? ___________________________
The radius of the nuclear forces? __________________________________________
Neptunium isotope nucleus 93 Np 237 having experienced a series of alpha and beta decays, it turned into a bismuth nucleus 83 Po 213 ... Determine the number of beta decays. ____________________
For 16 hours, the activity of the radioactive element decreased by 8 times. What is the half-life? ____________________________________________________
What is the approximate specific binding energy of the selenium nucleus 34 Se 79 ? ______________
Option 3.
Which scientist discovered 3 components radiation?
Boron; 2) Rutherford; 3) Becquerel; 4) Warehouse-Curie.
What is β-radiation?
The flow of electrons of different speeds;
The flow of helium nuclei;
Stream of high energy photons;
Neutron flux.
What kind of radiation can be stopped with a sheet of paper?
α; 2) β; 3) γ; 4) neutron radiation.
How many neutrons are in the uranium nucleus 92 U 238 ?
92; 2) 238; 3) 146; 4) 52.
Polonium isotope nucleus 84 Po 208 emits a γ particle. What element is formed?
84 Po 208 ; 2) 8 5 At 208 ; 3) 8 2 Pb 20 4 ; 4) 8 0 Hg 20 0 .
Strontium nucleus 38 Sr 90 has undergone beta decay and alpha decay. Determine the number of neutrons in the newly formed nucleus. What is this element? __________________
The radius of the nuclear forces? __________________________________________
Neptunium isotope nucleus 93 Np 237 after experiencing a series of alpha and beta decays, it turned into a polonium nucleus 84 Po 213 _________________________
For 16 hours, the activity of the radioactive element decreased by 2 times. What is the half-life?_________________________________
What is approximately the binding energy of the bromine nucleus 35 Br 79 ?_______________________
Option 4.
Which scientist has proved that 99.9% of the mass of an atom is in the nucleus?
Boron; 2) Rutherford; 3) Becquerel; 4) Warehouse-Curie.
What is α-radiation?
The flow of electrons of different speeds;
The flow of helium nuclei;
Stream of high energy photons;
Neutron flux.
What kind of radiation is a threat during a thermonuclear explosion?
α; 2) β; 3) γ; 4) neutron radiation.
How many neutrons are there more than protons in the uranium nucleus? 92 U 238 ?
92; 2) 238; 3) 146; 4) 52.
Polonium isotope nucleus 84 Po 208 emits a β-particle. What element is formed?
84 Po 208 ; 2) 8 5 At 208 ; 3) 8 2 Pb 20 4 ; 4) 8 0 Hg 20 0 .
Strontium nucleus 38 Sr 90 has undergone 2 beta decays. Determine the number of neutrons in the newly formed nucleus. What is this element? ___________________________
The radius of the nuclear forces? __________________________________________
Neptunium isotope nucleus 93 Np 237 having experienced a series of alpha and beta decays, it turned into a bismuth nucleus 82 Pb 213 ... Determine the number of β-decays. ________________________
For 6 hours, the activity of the radioactive element decreased by 4 times. What is the half-life? ____________________________________________________
What is approximately the binding energy of the selenium nucleus 34 Se 82 ? _ ______________________
Option5 .
Which scientist explained the radiation of the atom?
Boron; 2) Rutherford; 3) Becquerel; 4) Warehouse-Curie.
What is α-radiation?
The flow of electrons of different speeds;
The flow of helium nuclei;
Stream of high energy photons;
Neutron flux.
Where does an electron come from in a β-radioactive nucleus?
___________________________________________________________________
How many protons are in the uranium nucleus 92 U 238 ?
92; 2) 238; 3) 146; 4) 0.
Polonium isotope nucleus 84 Po 208 emits a γ-particle and an α-particle. What element is formed?
84 Po 208 ; 2) 8 5 At 208 ; 3) 8 2 Pb 20 4 ; 4) 8 0 Hg 20 0 .
Strontium nucleus 38 Sr 90 has undergone 2 beta decays and 2 alpha decays. Determine the number of neutrons in the newly formed nucleus. What is this element? _____________
The radius of the nuclear forces? __________________________________________
Neptunium isotope nucleus 93 Np 237 having experienced a series of alpha and beta decays, it turned into a bismuth nucleus 83 Po 213 ... Determine the number of β-decays.
For 8 hours, the activity of the radioactive element decreased by 4 times. What is the half-life?
What is approximately the binding energy of the selenium nucleus 34 Se 76 ?
Radioactivity and radiation hazardous objects
Exercise 1
Question:
What is radioactivity?
1) This is the ability of certain substances to emit harmful radiation
2) This is the phenomenon of spontaneous transformation of some atomic nuclei into others,
accompanied by the emission of particles and electromagnetic radiation
3) This is a phenomenon that allows the use of nuclear energy for peaceful purposes
Task # 2
Question:
What contributes to the natural background radiation?
1) Emissions from nuclear power plants
2) Solar radiation
3) Some elements contained in the Earth
Task # 3
Question:
What is a radiation hazardous facility?
Choose one of 3 answer options:
1) This is any object containing radioactive substances
2) This is an object that has been exposed to radioactive contamination
3) It is an object that is used, stored, processed or
transport radioactive substances
Quest # 4
Question:
Examples of radiation hazardous facilities are:
Choose several of the 4 answer options:
1
1) NPP
2) Places of burial of radioactive waste
3) Enterprises using hazardous chemicals
4) Object exposed to radiation contamination
Task # 5
Question:
How is an accident at an ROO classified in which a significant
release of radioactive substances and evacuation of the population is required within a radius of 25
km?
1) Accident with risk to environment
2) Serious incident
3) Severe accident
4) Global accident
Quest # 6
Question:
What is a radiation accident?
Choose one of 3 answer options:
1) This is the release of radioactive substances into the environment
2) This is a violation of the activities of any ROO
3) This is an accident at a radiation hazardous facility that leads to the release or
the release of radioactive products or the appearance ionizing radiation in
quantities exceeding the established norms for this object
Task # 7
Question:
Choose a substance that is not radioactive
Choose one of 4 answer options:
1) Uranus
2) Plutonium
3) Radon
4) Argon
2
Quest # 8
Question:
Rank the accident types by severity, starting with the most severe
Indicate the order of all 4 answer options:
__ Severe accident
__ Accident with risk to the environment
__ Serious incident
__ Global alarm
Quest # 9
Question:
What characterizes such a value as a half-life?
Choose one of 3 answer options:
1) The time of the decrease in the activity of radioactive radiation by half
2) The frequency with which the radioactive substance decays
3) The time during which the natural background radiation is halved
Quest # 10
Question:
Which of the following is not an RPO?
Choose one of 4 answer options:
1) Places of disposal of ships of the Navy
2) Enterprises of the oil industry
3) Uranium mining enterprises
4) Research nuclear reactors
Answers:
1) (1 p.) Correct answers: 2;
2) (1 p.) Correct answers: 2; 3;
3) (1 p.) Correct answers: 3;
4) (1 p.) Correct answers: 1; 2;
5) (1 p.) Correct answers: 3;
6) (1 p.) Correct answers: 3;
7) (1 p.) Correct answers: 4;
8) (1 p.) Correct answers:
Lesson number 49. Lesson topic. Phenomena confirming the complex structure of the atom. Radioactivity. Rutherford's experiments on dispersion a- particles. The composition of the atomic nucleus.
Lesson objectives: introduce students to the nuclear model of the atom;
foster a conscientious attitude towards learning, instill skills like independent workand teamwork;
to activate the thinking of schoolchildren, the ability to independently formulate conclusions, to develop speech.
Lesson type: learning new materials.
Lesson type: combined.
During the classes
Organizing time.
Updating students' knowledge.
Writing the concept of X-ray radiation.
Properties of X-rays.
The use of X-ray radiation.
Why do radiologists use gloves, aprons, and glasses containing lead salts?
The short-wavelength limit of light perception in some people is 37 ∙ 10 -6 cm. Determine the frequency of oscillations in these waves. (8.11 ∙ 10 15 Hz),
Learning new material
The hypothesis that all substances are composed of a large number of atoms originated over two millennia ago. The proponents of the atomic theory considered the atom as the smallest indivisible particle and believed that the entire diversity of the world is nothing more than a combination of invariable particles - atoms. Democritus' position: “There is a division limit- atom".Aristotle's position: "The divisibility of matter is infinite."
Concrete ideas about the structure of the atom developed as physics accumulated facts about the properties of matter. They discovered an electron, measured its mass and charge. Thought about electronic structure atom, first expressed by W. Weber in 1896, was developed by L. Lorentz. It was he who created electronic theory; electrons are part of the atom.
At the beginning of the century in physics there were a variety of and often fantastic ideas about the structure of the atom. For example, the rector of the University of Munich Ferdinand Lindemann in 1905 stated that "the oxygen atom has the shape of a ring, and the sulfur atom has the shape of a cake." The theory of "vortex atom" by Lord Kelvin continued to live, according to which the atom is arranged like rings of smoke emitted from the mouth of an experienced smoker.
Based on the discoveries, J. Thomson in 1898 proposed a model of the atom in the form of a positively charged sphere with a radius of 10 -10 m, in which electrons "float", neutralizing the positive charge. Most physicists were inclined that J. Thomson was right.
However, in physics for more than 200 years, a rule has been adopted: the final choice between hypotheses can only be made by experiment. Such an experience was set up in 1909 by Ernest Rutherford (1871-1937) with his colleagues.
Passing a beam of α-particles (charge + 2e, mass 6.64-1 (G 27 kg) through a thin gold foil, E. Rutherford found that some of the particles deviates at a rather significant angle from their original direction, and a small part α -particles are reflected from the foil.But, according to Thomson's atomic model, these α -particles, when interacting with foil atoms, should deviate by small angles, of the order of 2 °. However, a simple calculation shows that in order to explain even such small deviations, atoms of the foil can generate a huge electric field with a strength of more than 200 kV / cm.In Thomson's polyethylene ball, there can be no such voltages. Collisions with electrons are also not counted. After all, in comparison with them, an α-particle flying at a speed of 20 km / s, like a cannonball with a pea.
In search of a clue, Rutherford suggested to Geiger and Marsden to check: "and whether α-particles can bounce back from the foil."
Two years have passed. During this time, Geiger and Marsden counted more than a million scintillations and proved that about one out of 8 thousand α particles are reflected back.
Rutherford showed that Thomson's model was in conflict with his experience. Summarizing the results of his experiments, Rutherford proposed a nuclear (planetary) model of the structure of the atom:
1. An atom has a nucleus, the size of which is small in comparison with the size of the atom itself.
2. Almost all the mass of an atom is concentrated in the nucleus.
3. The negative charge of all electrons is distributed throughout the entire volume of the atom.
Calculations have shown that α -particles that interact with electrons in a substance are almost not deflected. Only a few α particles pass near the nucleus and experience sharp deflections.
Physicists took Rutherford's message with restraint. For two years, he himself also did not insist on his model very strongly, although he was sure of the infallibility of the experiments that led to it. The reason was as follows.
According to electrodynamics, such a system cannot exist, since an electron rotating according to its laws will inevitably and very soon fall onto the nucleus. I had to choose: either electrodynamics or the planetary model of the atom. Physicists silently chose the first. Silently, because it was impossible to either forget or refute Rutherford's experiments. Atomic physics has reached a dead end.
The total charge of electrons is equal to the charge of the nucleus, taken with a minus sign.
The total number of protons and neutrons in the nucleus is called the mass number - A.
The mass of a proton is 1840 times the mass of an electron.
Ζ is the charge of the nucleus. Mass number A \u003d Ζ + Ν.
The number of neutrons in the nucleus: Ν \u003d A-.
In the nuclei of the same chemical element, the number of neutrons can be different, while the number of protons is always the same.
Different types of the same element, which differ in the number of neutrons in the nucleus, are called isotopes.
III. Securing the material
What is the essence of Thomson's model?
Draw and explain a diagram of Rutherford's experiment on scattering - α particles. What do we observe in this experience?
Explain the reason for the scattering of α-particles by atoms of matter?
What is the essence of the planetary model of the atom?
Determine the composition of the nuclei of silver, mendelevium, cobalt.
IV. Lesson summary
§ 52-53. Exercise 42. Problems with a problem book by A.P. Rymkevich
Atomic nucleus test
Option 1.
1. The figure shows the models of atoms. What is the number marked by Thomson's model of the atom?
AND.1 B.2 IN.3
2. In Rutherford's model of the atom:
AND.The positive charge is concentrated in the center of the atom, and the electrons revolve around it. .
B. The negative charge is concentrated in the center of the atom, and the positive charge is distributed throughout the entire volume of the atom. .
IN.
3. What is the number marked on the scheme of the Rutherford installation for the source of particles?
AND. 1 B. 2 IN.3 G. 4
4. Electrons cannot change the trajectory - particles in Rutherford's experiments, because
AND. The charge of an electron is very small compared to the charge of a particle.
B... The mass of an electron is much less than the mass of a particle.
IN. An electron has a negative charge, and a particle is positive.
6. Planetary model atom suggested
AND.Thomson.
B. Democritus
IN. Rutherford.
7. Rutherford's experiment on scattering - particles proves:
AND.
B.
IN
Atomic nucleus test
Option 2
Choose one correct statement.
1. The figure shows the models of atoms. What is the number marked by Rutherford's model of the atom?
AND.1 B.2 IN.3
2.In Thomson's model of the atom:
AND... The positive charge is concentrated in the center of the atom, and the electrons revolve around it. .
B. The positive charge is concentrated in the center of the atom, and the stationary electrons are dispersed around it .
IN. The positive charge is dispersed throughout the entire volume of the atom, and electrons are interspersed into this positive sphere.
3. What charge does a particle have?
AND... Negative. B... Positive. IN... Neutral.
4. What number on the diagram of the Rutherford installation marks the foil in which the scattering of particles occurs?
AND. 1 B. 2 IN.3 G. 4
5. Democritus states:
AND... An atom is the smallest indivisible particle of matter.
B... The atom is a "raisin muffin".
IN. In the center of the atom there is a small positive nucleus, and electrons move around it.
6. What - the particle flies on the comparative great distance from the core?7. Rutherford's experiment on scattering - particles proves
AND.The complexity of radiation.
B.The ability of some atoms chemical elements to spontaneous radiation.
IN. Inconsistency of Thomson's model of the atom.