The right-hand rule was made by Marie Curie in the course of their studies.
She noted that the residual material was producing more by a magnetic field on a moving radiation than the pure material.
Theore con # Relate mass to energy using tained new chemical elements that also produced radiation was hypothesised by Marie Curie.
The special theory of relativity required processing tons of the radioactive material.
The 1903 Nobel Prize in physics was shared by the Curies and Henri Becquerel.
Marie Curie was awarded a second prize for her discoveries of radium and polonium.
The mechanism by which radiation was produced was not under scrutiny for a while.
The structure of the atomic nucleus is considered in this chapter.
A small fraction of positively charged alpha particles passing through a thin gold foil would bounce back after colliding with the gold nucleus.
The nucleus occupied about 10% of the atom's volume, but still contained 99% of the atom's mass.
We review the findings in this section.
The third generation of a family of French scientists was very interested in Roentgen's X-rays.
In 1896, Becquerel worked with potassium uranyl sulfate crystals.
Exposure to sunlight would cause these crystals to light up.
The images on photographic plates would be produced by the crystals.
Scientists thought that photographic plates could only be exposed by light, ultraviolet rays, and X-rays.
The Sun's energy was sorbed by the uranium crystals that they caused them to emit X-rays.
The images on the photographic plates were formed by crystals that had not been exposed to sunlight.
This meant that there was no external source of energy.
An external magnetic field wouldn't help them if they did.
He found that the field reflected the rays.
They were charged because they were electrical and used for investigations.
The magnetic field reflected the rays in two different directions.
The idea that the rays contained both positively and negatively charged particles was consistent with what he found.
The work of Pierre and Marie Curie continued in 1896.
Dry air and mally contain mostly neutral particles, which means that a charged electrical device can stay in a dry room for a long time.
When placed near a sample containing ura nium salts, an electric meter discharges much more quickly.
One can see the ion concentration in the air by recording the time it takes the electrical device to discharge.
The discharge time and mass of the ion concentration were measured by Marie Curie.
In half the time, the mass of the same salt was doubled.
She used various uranium salts in which the ion concentration depended on the presence of the concentration of the radioactive substance and not on the particular uranium salt that was discharged from the device.
The ion concentration did not change when she varied the amount of light.
The ion concentration did not change when she varied the temperature.
The sample of the ion concentration was the same as before.
Changes in the amount of light shining on a sample did not change the amount of radiation produced by the salts.
The electrons in the atoms were not to blame for the rays.
The nuclei of atoms must be the source of the Becquerel rays.
An electric current was caused by the abil ionize caused by radiation.
There was no current in the circuit because the air between the plates was di electric.
A current was detected after the Uranium was placed between the plates.
The metal layers affect the amount of radiation.
As he added more sheets, the amount of current decreased, but only if he didn't present a point.
Even with the addition of more aluminum sheets, there was no further decrease in radioactivity.
The radia tion consisted of at least two components, one of which was not absorbed by the aluminum sheets.
The charged particles that were absorbed by the aluminum sheets were part of the radiation.
The particles should be repelled by a magnetic field.
The magnetic field should not affect the rays if there were no charged particles.
According to the right-hand rule, if the radiation is positive, the screen should glow in three places: from the radioactive particles, one straight ahead, and one down.
If the radiation contains negatively charged particles, the magnetic field should move them downward.
The downward-deflected negatively charged particles have a smaller mass-to-charge ratio than the upward-deflected positively charged particles.
The particles were charged with a mass-to-charge ratio twice that of a hydrogen ion using more powerful magnets.
The alpha particles that were used to probe the structure of the atom are the same particles that were used later.
Many elements with high atomic num bers were found to be radioactive.
Some elements with low atomic numbers were also radioactive.
The nucleus of an atom is made of positively charged alpha parti cles and negatively charged electrons.
They are held together by their attraction.
When new findings emerged, the model was modified to provide a start for nuclear physics.
An alpha particle is heavier than a hydrogen atom.
When alpha particles were shot into nitrogen gas, they moved in curved paths that indicated they were positively charged.
The particles had the same charge magnitude as an electron and mass as a hydro Gen nucleus, according to further testing.
The nucleus of hydrogen is the protons.
A new model of the nucleus began to emerge as the protons became an important part.
In the nuclear model, alpha particles and electrons were thought to be the primary nuclear constituents, thanks to the uncertainty principle discussed in Chapter 27.
The principle states that if an electron is confined within uncertainty principle, its speed would be greater than light speed.
The uncertainty principle can be used to estimate its momentum.
Think about a carbon nucleus.
There must be 6 more protons than electrons in the nucleus.
The value is less than a tenth of the electron's energy.
The result shows that an electron in the nucleus would quickly escape.
The form of carbon does not emit electrons.
Reasoning similar to that of other nuclei.
elec trons can't be components of the nucleus because of the uncertainty principle.
The mass of a protons was four times that of 2.
The alpha could not be made with two protons.
A neutral parti cle with the approximate mass of a protons was suggested by Rutherford in 1920.
The hypothesis stimulated a search.
The search was complicated by its electrical neutrality because ex perimental techniques could only detect charged particles.
The first step in the search for a new particle and a new nuclear model was taken by Walter Bothe and Herbert Becker.
The neutral radiation left the beryllium atoms after they bombarded them with al pha particles.
The initial radiation was thought to be high energy.
Frederic Joliot-Curie, one of Marie Curie's daughters, and her husband, used a stronger source of alpha particles to repeat Bothe's experiment.
Bothe bombarded beryl ium atoms with alpha particles.
They put a block of paraf fin beyond the beryl ium and a particle detector beyond the paraffin in their experiment.
The neutral radiation ejected the beryl ium protons from the paraffin.
The Joliot-Curies made a reasonable assumption that visible and high-frequency rays could knock out protons from a metal surface and that high-frequency rays could knock out electrons from a metal surface.
The Joliot-Curie experiments were repeated by James Chadwick.
He placed a detector.
The energies and momenta of the Alpha particles were compared.
The particles are about the same mass as the protons.
The prize for this work was awarded in 1935.
The realization that electrons were not part of the nucleus was a major factor in revising ideas of nuclear structure.
The electric charge of many nuclei is not accounted for by alpha particles.
A new model of nuclear particles was created from protons and neutrons.
The extra mass was accounted for by the un charged neutrons.
Alpha particles are not enough to make a boron nucleus.
The number of neutrons in the nucleus is what is known as a boron nucleus.
The mass of atoms and nuclei are very small.
The mass spectrometer is a device that scientists use to measure the mass of an elementary particle by observing its motion in a magnetic field.
Mass spectrometers are used to measure the mass of ionized atoms.
The force of the magnetic field on the positive pass through a region with a high potential difference causes carbon ion to go to high speeds.
The force on the take is assumed to be.
If we assume that the number of neutrons is different, the differences in mass can be explained.
Carbon comes in three naturally occurring forms: 126C, 136C, and 146C.
There are six protons in each isotope.
The chemical behaviors of elements are almost the same because of their electronic structure.
The nuclei behave differently.
Only a smal number of the elements are stable.
We will consider the rest soon.
The element is determined by 2 in the symbol.
An element of copper is copper-63.
It is not an exact number.
You can see the individual isotopes in the appendix.
Let's compare the repulsive force that two protons exert on each other when inside a nucleus with the force that a protons exerts on an electron in the atom.
The system is made of protons.
The nuclear force needs to be nearly zero very quickly with increasing distance between nucleons.
Not every nucleon is attracted to every other one, because some of them are far away.
Experiments show that the two nuclei are stable.
The nuclear force involves only the nearest neighbor.
There is a strong nuclear attraction between a protons and its neighbors.
Let's look at another prediction based on zero force due to the hypothesis of this attractive nuclear force.
In order to separate the electron from the protons in the hydrogen atom, we must add energy to the system.
The electron becomes unbound from the nucleus when the sum of added energy, electrical potential energy, and kinetic energy is zero.
We could make similar statements about the nucleus.
The nucleus has a binding energy that must be added to separate it from its components.
The compo has a lot of energy.
The rest energy of the protons and neutrons is what composes it.
The nuclear potential energy of the nucleus, the electric potential energy of the nucleus, and the kinetic energy of the protons and neu trons all contribute to a negative number.
The nucleus's rest energy is the sum of four contributions.
The rest energy of the nucleus should be less than the rest energy of the Nuclear force and binding energy.
The total mass of the nucleus should be less than its mass.
We need to collect data on the nucleus's mass to see if this prediction matches ex perimental evidence.
We look at ents.
The outcome of the experiment was matched by our prediction.
Helium is not unique in having a smaller mass.
The nucleus of lithium 73Li is made of three protons and four neu trons.
There are three electrons in the atom.
The mass of the three hydrogen atoms and four neutrons is less than the mass of the lithium atom.
The mass of the hydrogen atom is used to account for the mass of the electrons.
The mass of the electrons is canceled when the mass of the atom is subtracted.
It's easier to measure the mass of atoms than it is to measure the mass of the nucleus, which is why it's more useful to define mass defect in terms of the mass of atoms.
The mass defect of a helium nucleus was determined in the testing experiment table.
The binding energy of the atomic nucleus is related to this defect.
Mass defect is easily expressed in atomic mass units, where 1 MeV is 106 eV.
The mass defect of a nucleus can be quickly converted into binding energy.
There are 2 units of energy.
The binding energy of the nucleus of sodium-23 12311Na2 is 187 MeV; for lith ium-7 173Li2, the binding energy is 39.2 MeV; and earlier we found that the binding energy of helium-4 was 28.3 MeV.
The differences mean that more energy is needed to separate a sodium-23 atom from hydrogen atoms and neu trons than it is to separate a lithium-7 atom from hydrogen atoms and neutrons.
There is an "un fair" advantage to the total binding energy that sodium has.
The binding energy per nucleon is 1187 MeV2>123 nucleons2 It is 139.2 MeV2>17 nucleons2 for lithium-7 and 128.3 MeV2>14 nucleons2 for helium-4.
We can see that the nucleus of sodium is more stable than the nucleus of helium.
Nuclear reactions 1053 separate the sodium nucleus into its components than is needed for the helium nucleus, and the least stable is the lithium nucleus.
The indicator of nuclear stability is the amount of binding energy per nu cleon.
The first person to transmute one element into another was Ernest Rutherford, who did it in 1919.
Nuclear reactions involve the transformation of re actants into different products.
The number of each type of atom remains the same in a chemical reaction.
Different elements are created in a nuclear reaction.
Two nuclei may interact to form one or more new ones.
A nucleo may split into two or more new nuclei, or even emit a smal particle, leaving behind a different nucleus.
The advantage of writing nuclear reactions is that atomic mass tables can be used to analyze the energy transfor mations that occur during the reactions.
Even though atomic mass is used, the energy transformations are associated with the reactant and product nuclei.
The number of atoms must be the same before and after a chemical reaction.
Rules apply to nuclear reac tions.
There are rules for allowed nuclear reactions.
The reaction rules can be used to include it.
It wouldn't violate charge conserva tion if a neutron vanished, but they don't seem to do that.
They can transform protons into something, but they can't disappear.
We don't have a reason for this pattern, but we will return to it in Chapter 29 The stability of matter in the uni verse is explained by this rule.
The two rules are summarized.
To figure out the prod neutron 10n.
The unknown product has to remain constant throughout the reaction.
The products had more energy than the reactants.
Some of the rest mass energy of the reactants could be converted to energy.
The mass of the reac tants should be greater than the mass of the products.
Is this consistent with the idea that reactants, as predicted?
The products will have more energy than the reactants.
The opposite can happen.
The reactants have more energy than the products in certain nuclear reactions.
The rest energy of the products is more than that of the reactants.
Both types of reac tions can be understood.
There are several opportunities to use this idea.
He missed an important impact on early atomic and nuclear physics.
Nuclear reactions can be a source of power.
60 have the most binding energy per nucleon, while small and large nuclei have less.
The energy should be released when the two smal nuclei combine.
Energy should be released when a nucleus breaks.
Both of these processes happen in nature.
Due to their positive electric charges, 6 602 do not spontaneously join to form heavier ones.
The nucleus must be very close to each other in order for the nuclear force to bind them together.
Their lives begin with mostly hydrogen and a small amount of helium.
The temperatures and pressures needed to test the limits of current technology are what could potentially make fusion a source of clean energy.
Stars with mass produce elements from helium to carbon through fusion.
There are elements up to iron.
The Sun ex plodes at the end of their lives, whereas stars are much more massive.
The elements heavier than iron are known as supernovas.
The chemical composition of the uni verse is influenced by explosions.
The elements are lighter than iron when they are in the stars' cores.
Iron that is produced during the explosion is thrown into space.
The Sun and Earth are made of elements that were produced long ago inside stars that exploded as supernovas.
Many of the atoms in our bodies came from these supernovas.
Determine the amount of energy released in the chain of reactions.
The mass 1 is released in a typical chemical reaction.
The rest of the reactant was verted to other forms.
The reac tion stops once the reactants have been used up.
The Sun will run out of hydrogen and start burning it into carbon eventually.
Our star will go dark as fusion will cease as the Sun is not large enough to make carbon.
The models of the stel ar structure show that the fusion reactions in the central parts of stars have favorable conditions.
2.5 times the age of Earth is what this result is.
The star takes less time to form a nucleus than the Sun does.
The rate at which the energy is radiated is the same as the rate at which the Sun is duced.
The heavy nuclei do not spontaneously split.
The nucleus gets more energy when the neutron enters it.
The heavy nucleus is increasing its energy.
The excited nucleus divides into two and a moving neutron.
A chain reaction can occur when the new neutrons hit other hea nuclei.
The equilibrium of the nu 236cl U*eus causes it to fall apart and produce a chain reaction.
Usually y have a lower ratio.
A chain reaction is produced by 92U S 141 56Ba + 92 36Kr + 310n + energy nuclei.
The above reaction releases energy.
A chain reaction can be created by the new neutrons.
Your friend says that nuclear power produces a chain reaction.
The appropriate values were put in a nuclear power plant.
The historical experiment performed by German scientists in the 1930s is depicted in Quantitative Exercise 28.6.
Their goal was to make elements heavier than uranium.
They thought that bombarding uranium with neutrons would lead to the capture and decay of the protons in the nucleus, thus creating heavier elements.
They were surprised that the nuclei produced in the reaction were similar to those of barium and other nuclei.
They couldn't explain the result.
Meitner had to flee Germany because he was a Jew.
She moved to Sweden.
She asked her nephew Otto Robert Frisch to help with the explanation of the results.
The nucleus was modeled as a drop of water in which surface tension holds the water together, but in this case it is the nuclear forces that hold the nucleons together.
There are too many charged protons in heavy nuclei.
If the nucleus was not spherical, the protons would repel each other and overwhelm the surface tension.
The model suggested that the nucleus could be stretched and divided into two pieces.
This meant that the nucleus of the nuclear bomb would be very unstable and ready to break if provoked.
The model for fission was created by Meitner and Frisch.
142He2 is one of the most stable small nuclei.
A repulsive alpha particle is created by the release of protons and two neutrons in a helium nucleus.
An alpha particle is released when radium undergoes this decay.
The radium nucleus's rest energy was converted into the product's energy.
The remaining 0.2 MeV is converted to energy by the recoiling lead-208 nucleus.
The energy fraction of the energy may be released as an additional use equation.
2 thorium is undergoing alpha decay.
An electron is emitted from a nucleus.
From the uncertainty principle, we know that electrons can't reside in the nucleus.
There is a possibility that a nucleus can spontaneously decay into a protons and an electron.
The electron leaves the nucleus while the protons stay inside.
The total electric charge and total nucleon number on both sides of the equation are the same.
Ernest Rutherford and Frederick Soddy were studying radioactive decay.
Another prediction is that the heavier elements should produce more radiation than the lighter elements.
The spin quantum number was used in many other experiments.
During the decay of a neu tron, all three participating particles have spin values equal to 1>2.