question

who discovered radioactivity?

answer

Becquerel, Marie Curie, Pierre Curie

question

radioisotope

answer

form of an atom that is unstable & loses particles from the nucleus

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alpha particle

answer

radiation composed of 2 protons and 2 neutrons

question

beta particle

answer

composed of fast-moving electrons

question

charge of a beta particle?

answer

-1

question

charge of an alpha particle?

answer

+2

question

gamma radiation

answer

high energy electromagnetic radiation given off as PART of a decay

question

compare the subatomic particles involved in nuclear and chemical reactions

answer

protons, electrons, and neutrons can be invloved in cuclear change; only electrons are involved in chemical change

question

how do you know whether the reaction is chemical or nuclear when an atom undergoes a reaction and attains a more-stable form.

answer

if the new, more stable form of the atom has an identitiy different from the original atom or gamma radiation has been released, a nuclear process has occurred

question

compare and contrast chemical reactions and nuclear reactions in terms of energy changes and the particles involved.

answer

nuclear reactions release more energy per mole. nuclear reactions involve neutrons and protons, wehreas chemical reactions involve electrons

question

what is the difference between x-rays and gamma rays?

answer

x-rays are produced by materials that are in an excited electron state. gamma rays are produced by radioactive sources.

question

transmutation

answer

the conversion of one atom to another type by changing the nucleus The atomic number is altered Whether an atom spontaneously decays and what type if radiation it emits depends on its neutron to proton ratio

question

Nucleons

answer

Protons and neutrons are referred to as

question

Neutron to proton ratio

answer

The stability of a nucleus can be correlated to its neutron to proton (n/p) ratio For atoms with low atomic numbers (<20), the most stable nuclei are those with 1:1 n/p As atomic numbers increase more and more neutrons are needed to produce a strong nuclear force that is sufficient to balance the electrostatic repulsion force between protons. The n/p will gradually increase to 1.5:1

question

Beta decay

answer

Type of decay that decreases the number of neutrons in the nucleus

question

Alpha decay

answer

All nuclei with more than 82 protons are radioactive and decay spontaneous. These very heavy nuclei often decay by emitting alpha particles

question

For nuclei with low n/p what are two common radioactive decay processes?

answer

Positron emission and electron capture These 2 processes tend to increase the n/p ratio bringing the atom closer to the band if stability

question

positron emission

answer

radioactive decay process that involves the emission of a positron from a nucleus. a positron is a particle with the same mass as an electron but opposite charge, thus, it is represented by the symbol e^+ or beta^+ during positron emission, a proton in the nucleus is converted into a neutron and a positron and then position is emitted

question

electron capture

answer

ocurs when the nucleus of an atom draws in a surrounding electron, usually one ferom the loswet energy level. this captured eledtron combines with a proton to form a neutron the atomic number of the nuclues decreases by 1 as a resoult of electron capture

question

describe what happens to an unstable nucleus

answer

unstable nuclei decay by emnitting alpha or beta radiation until they form a stable element

question

radioactivity

answer

penetrating rays & particles given off by unstable nuclei

question

half-life

answer

the amount of time for 1/2 the radioactive nucleus to decay

question

describe the forces acting on the particles within a nucleus and explain why neutrons are the glue holding the nucleus together

answer

protons are positively charged and repel each other. neutrons do not repel easch other or protons. the sterong nuclear force is an attractive force that acts on both protons and neutrons in the nucleus. the greater the number of neutrons in the nucleus, the greater the ftrong nuclear force.

question

trans uranium elements

answer

elements with atomic numbers greater than 93 and have been produced in the laboratory by induced transmutaion and are radioactive

question

einstein's equation

answer

the equation relates mass and energy. it states that any reaction produces or consumes energy due to a loss or gain in mass. energy and mass are equivalent.

question

mass defect

answer

the difference in mass between a nucleus and its component nucleons the mass of the nucleus is always less than the sum of the masses of the indivieual protons and neutrons that comprise it.

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nuclear FISSION

answer

the splitting of a nucleus into smaller, more stable fragments the fission of a nucleus is accompanied by a very large release of energy

question

nuclear FUSION

answer

the process of binding smaller atomic nuclei into a single larger and more stable nucleus.

question

in fission, what is the large nuclei split by?

answer

neutrons

question

T/F Great amounts of energy can be liberated from small amounts of matter in nuclear reactions.

answer

True

question

T/F The amount of U-235 in a nuclear reactor should always be kept subcritical

answer

False

question

T/F Nuclear power plants do not contribute to pollution

answer

T-air pollution F-nuclear waste

question

T/F Inserting boron or cadmium rids into the reactor core can control a fission reaction

answer

True

question

Describe the process that occurs during a nuclear chain reaction and explain how to monitor a chain reaction in a nuclear teactir

answer

A neutron strikes a target nucleus such as u-235, which then splits into multiple fission fragments and releases several neutrons. These neutrons collide with other nuclei, causing additional fissions and sustaining the reaction. To control the chain reaction in a nuclear reactor, control rods if cadmium and boron are used to absorb some of the neutrons released during the reaction.

question

How can nuclear fission be used to generate electric power?

answer

Fission reactions heat water and form steam. The steam spins turbines that produce electric power.

question

Relate binding energy per nucleon to mass number.

answer

The binding energy per nucleon reaches a maximum value fir mass numbers around 69amu.

question

Describe what is meant by subcritical mass and supercritical mass.

answer

The mass is subcritical if most of the neutrons escape the material instead of hitting other material. The mass is supercritical if most neutrons hit other material.

question

How is it possible that both the splitting of nuclei (fission) and the combining of nuclei (fusion) release tremendous amounts of energy?

answer

With fission, A large nucleus splits into smaller nuclei.the binding energy of the large nucleus is greater than the sum of the binding energies of the smaller nuclei. That difference in energy is released. With fusion, two smaller nuclei combine to form a larger nuclei.the sum of the binding energies of the smaller nuclei is greater than the binding energy of the larger nucleus. Again the difference in energy is released.

question

Describe the current limitations of fusion as a power source.

answer

A lot of energy is required to initiate the reaction. Currently no materials are capable of withstanding the very high temperature reached during reactions.

question

O ; o o is an example of what process?

answer

fission

question

o o ; O is an example of what process

answer

fusion

question

fusion or fission produces hazardous waste?

answer

fission

question

what does fusion produce?

answer

helium

question

above the atomic number 20, there are more _______ than protons

answer

neutrons

question

critical mass

answer

the minimum mass of a sample of fissionable material necessary to sustain a nuclear chain reaction.

question

0/-1 e is what decay?

answer

beta decay

question

4/2 He is what decay?

answer

alpha decay

question

atomic #s below 18 have a __:__ stability ratio

answer

1:1

question

penetrating power of the 3 main types of radiation:

answer

A ; | B ; | ; | C ; | ; | ; |

question

list three methods for detecting or measuring radiation

answer

1. Geiger counter 2. scintillation 3. film ID badge

question

1/0 n -; 1/1 p + 0/-1 e + anti neutrino is what process?

answer

going from neutron -; proton (+ beta particle)

question

how to get a proton from a neutron:

answer

beta decay

question

proton to neutron process is called:

answer

positron emission

question

1/1 p -; 0/-1 e + 1/0 n + neutrino is what process?

answer

positron emission

question

the area of a nuclear stability graph plotted with stable nuclei is called...?

answer

the band of stability

question

protons and neutrons are referred to as:

answer

nucleons

question

induced transmutation is caused by what...?

answer

bombarding a nucleus with high-velocity particles

question

what does induced transmutation do?

answer

changes it to a new element

Chapter 25; Nuclear Chemistry – Flashcards

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