GE-CHEM 1103 Module 4.2

Question 1

composed of the
two nucleons, protons and neutrons

Answer 1

nucleus

Question 2

number of protons

Answer 2

atomic number (Z)

Question 3

number of protons and neutrons together

Answer 3

mass number (A)

Question 4

Not all atoms of the same element have the
same mass, due to different numbers of
neutrons in those atoms

Answer 4

Isotopes

Question 5

nuclei change spontaneously,
emitting radiation

Answer 5

radioactive and refer to these nuclei’s as radionuclides

Question 6

show how
these nuclear reactions occur

Answer 6

nuclear equations

Question 7

atoms and
charges need to balance

Answer 7

chemical equations

Question 8

atomic number
and mass number need to balance

Answer 8

nuclear equations

Question 9

Has a charge of 2+, a mass of 6.64x10^-24 g, a relative penetrating power of 1 and its nature of radiation is 4(A) 2(Z) He nuclei

Answer 9

α

Question 10

Has a charge of 1-, a mass of 9.11x10^-28 g, a relative penetrating power of 100 and its nature of radiation is electrons

Answer 10

β

Question 11

Has a charge of 0 , a mass of 0 g, a relative penetrating power of 10000 and its nature of radiation is high-energy photons

Answer 11

γ

Question 12

How far do the alpha, beta, neutron and gamma radiation pass through materials

Answer 12

paper(alpha) > hand (skin) > metal(beta) > water (neutron)> concrete > lead(gamma)

Question 13

Nuclear Equation:
(A)(Z) X > (A-4)(Z-2) Y + 4(A) 2(Z) He
Change in atomic no.: -2
Change in mass no.: -4

Answer 13

Alpha decay

Question 14

Nuclear Equation:
(A)(Z) X > (A)(Z+1) Y + 0(A) -1(Z) e
Change in atomic no.: +1
Change in mass no.: no change

Answer 14

Beta decay

Question 15

Nuclear Equation:
(A)(Z) X > (A)(Z-1) Y + 0(A) +1(Z) e
Change in atomic no.: -1
Change in mass no.: no change

Answer 15

Positron emission

Question 16

Nuclear Equation:
(A)(Z) X + 0(A) -1(Z) e > (A)(Z-1) Y
Change in atomic no.: -1
Change in mass no.: no change

Answer 16

Electron capture

Question 17

loss of an α-particle
(He-4 nucleus, two protons and two neutrons):

Answer 17

Alpha decay

Question 18

is the loss of a β-particle (a
high-speed electron emitted by the nucleus)

Answer 18

Beta decay

Question 19

is the loss of a γ-ray,
which is high-energy radiation that
almost always accompanies the loss of
a nuclear particle

Answer 19

Gamma emission

Question 20

a particle that has the same
mass as, but an opposite charge to, that
of an electron

Answer 20

positron

Question 21

Some nuclei decay by emitting a
positron

Answer 21

Positron Emission

Question 22

An electron from the surrounding electron
cloud is absorbed into the nucleus

Answer 22

electron capture

Question 23

Writing Nuclear Equations for
Nuclear Transmutations

Answer 23

Example
(A)(Z) X(α, p) (A)(Z) Y

Question 24

first-order process

Answer 24

Radioactive decay

Question 25

The kinetics of such a process obey this equation

Answer 25

ln(Nt/No) = -kt

Question 26

time required for half of a radionuclide sample to decay.

Answer 26

Half-life

Question 27

Formula of k constant

Answer 27

k = ln 2 (or 0.693)/t 1/2

Question 28

radioisotopes used to study a chemical reaction

Answer 28

Radiotracers

Question 29

An element can be followed through a reaction

Answer 29

to determine its path and better understand the mechanism of a chemical reaction

Question 30

react chemically exactly the same as nonradioactive nuclei of the same element

Answer 30

Radionuclides

Question 31

Medical Application of Radiotracers

Answer 31

1. wide diagnostic use in medicine 2. administered to a patient (usually intravenously) and followed. Certain elements collect more in certain tissues, so an organ or tissue type can be studied based on where the radioactivity collects.

Question 32

* A compound labeled with a positron emitter is injected into a patient. * Blood flow, oxygen and glucose metabolism, and other biological functions can be studied. * Labeled glucose is used to study the brain, as seen in the figure to the right.

Answer 32

Positron Emission Tomography (PET Scan)

Question 33

There is a tremendous amount of energy stored in nuclei. * Einstein’s famous equation, E = mc2 relates directly to the calculation of this energy.

Answer 33

Energy in Nuclear Reactions

Question 34

associated with making and breaking chemical bonds

Answer 34

Chemical energy

Question 35

due to changes in the nucleus of atoms changing them into different atoms

Answer 35

Nuclear energy

Question 36

13% of worldwide energy

Answer 36

nuclear energy

Question 37

Commercial nuclear power plants

Answer 37

fission

Question 38

Bombardment of the radioactive nuclide with a neutron starts the process

Answer 38

Nuclear Fission

Question 39

Neutrons released in the transmutation strike other nuclei, causing their decay and the production of more neutrons. (note: This process continues on and on)

Answer 39

chain reaction

Question 40

rate of neutron loss > rate of neutron creation by fission

Answer 40

Subcritical mass

Question 41

rate of neutron loss = rate of neutron creation by fission

Answer 41

Critical mass

Question 42

rate of neutron loss < rate of neutron creation by fission

Answer 42

Supercritical mass

Question 43

The minimum mass that must be present for a chain reaction to be sustained

Answer 43

critical mass

Question 44

the heat generated by the reaction is used to produce steam that turns a turbine connected to a generator.

Answer 44

nuclear reactors

Question 45

What does The reactor core consists?

Answer 45

fuel rods, control rods, moderators, and coolant

Question 46

block the paths of some neutrons, keeping the system from reaching a dangerous supercritical mass

Answer 46

control rods

Question 47

* Reactors must be stopped periodically to replace or reprocess the nuclear fuel. * They are stored in pools at the reactor site. * The original intent was that this waste would then be transported to reprocessing or storage sites. * Political opposition to storage site location and safety challenges for reprocessing have led this to be a major social problem.

Answer 47

Nuclear Waste

Question 48

When small atoms are combined, much energy is released. This occurs on the Sun. The reactions are often called thermonuclear reactions.

Answer 48

Nuclear Fusion

Question 49

more harmful to living systems

Answer 49

Ionizing radiation

Question 50

any type of electromagnetic radiation that does not carry enough energy per quantum to ionize atoms or molecules that is, to completely remove an electron from an atom or molecule.

Answer 50

nonionizing radiation

Question 51

depends on the type of radioactivity, the length of exposure, and whether the source is inside or outside the body.

Answer 51

damage to cells

Question 52

Outside the body it is the most dangerous

Answer 52

gamma rays

Question 53

Inside the body it can cause most harm

Answer 53

alpha radiation

Question 54

* Low-level, long-term exposure can cause health issues. * Damage to the growth-regulation mechanism of cells results in cancer.

Answer 54

Exposure in radiation