Chapter 17 Radioactivity and Nuclear Chemistry

Question 1

Radioactivity

Answer 1

the emission of tiny, invisible particles by the nuclei of certain atoms

Question 2

Radioactive

Answer 2

the atoms that emit particles

Question 3

Phosphorescence

Answer 3

long-lived emission of light that sometimes follows the absorption of light by some atoms and molecules

-the glow in glow-in the-dark toys absorb light and re-emits it

Question 4

Alpha Radiation

Answer 4

• occurs when an unstable nucleus emits a small piece of itself consisting of 2 protons and 2 neutrons
• highest ionization power
• lowest penetrating power
• dangerous when digested/inhaled, not dangerous when outside of body

Question 5

Nuclear Equation

Answer 5

• an equation that represents the changes that occur during radioactivity and other nuclear processes
• the identity of an element changes
  ex) alpha decay of U-238

²³⁴₉₂ U → ²³⁰₉₀Th +⁴₂He

parent daughters

Question 6

Parent Nuclide

Answer 6

original atom that forms daughter nuclides in a nuclear equation

Question 7

Daughter Nuclides

Answer 7

the products in the nuclear equation that forms an element + an alpha particle (⁴₂He)

Question 8

Ionizing Power

Answer 8

• the ability of radiation to ionize molecules + atoms
• ionization in living cells causes damage, destruction, or abnormal reproduction

Question 9

Penetrating Power

Answer 9

• ability to penetrate matter
• the smaller the size of the particle, the higher the penetrating power

(like a semi-truck in a traffic jam, large has low penetrating power)

Question 10

Alpha Particle

Answer 10

• results from alpha radiation
• composed of 2 protons + 2 neutrons
• symbol is ⁴₂He
• largest of all particles emitted by radioactive nuclei

Question 11

Beta Radiation

Answer 11

• occurs when an unstable nucleus emits an electron by converting a neutron to a proton
• intermediate ionizing power
• intermediate penetrating power
• 1 Neutron→Proton+Electron

ex)

²²⁸₈₈Ra→²²⁸₈₉Ac + ⁰_-1e

Question 12

Beta Particle

Answer 12

-midsize particles

⁰_-1e

Question 13

Gamma Radiation

Answer 13

• electromagnetic radiation
• emits gamma rays usually with the alpha emission
  ex) ²³⁸₉₂U > ²³⁴₉₀Th + ⁴₂He + ⁰₀y

Question 14

Gamma Rays

Answer 14

• high energy (short wavelength) photons
• no charge, no mass
• low ionization power
• high penetrating power

symbol is ⁰₀y

Question 15

Positron Emission

Answer 15

• proton changes into a neutron and emits a positron
• intermediate ionizing power
• intermediate penetrating power
  ex) ³⁰₁₅P → ³⁰₁₄Si + ⁰₊₁e

Question 16

Positron

Answer 16

-has the mass of an electron but carries a positron but carries a 1+ charge

symbol is ⁰₊₁e

Question 17

Thermoluminescent Dosimeters

Answer 17

-radiation detector which are issued to people working w or near radioactive substances

Question 18

Geiger-Muller Counter

Answer 18

• device that detects radioactivity
• particles emitted by radioactive nuclei pass thru an argon-filled chamber;

energetic particles create a trail of ionized argon atoms

Question 19

Scintillation Counter

Answer 19

device to detect radiation instantly

-radioactive emission passes thru a material (like NaI or CsI) that emits ultraviolet/visible light in response to the excitation of energetic particles

Question 20

Half-Life

Answer 20

the time it takes fr half of the parent nuclides in a radioactive sample to decay into daughter nuclides

• short half-lives = high activity (many decay events per unit of time)
• long half-lives = low activity

Question 21

Radiocarbon Dating

Answer 21

a technique used to estimate the age of fossils and artifacts

Question 22

Nuclear Fission

Answer 22

splitting of a heavy nucleus to form 2 or more lighter ones + energy

• emits an enormous amount of energy
  ex) the nucleus of a neutron-bombarded Uranium had broken apart into Barium, Krypton, + other smaller particles

Question 23

Critical Mass

Answer 23

the mass required to induce a chain reaction

Question 24

Nuclear Fusion

Answer 24

• combination of 2 light nuclei to form a heavier one
• emits a large amt of energy
• energy source of stars + sun
• bases of hydrogen bombs

Question 25

units of radioactivity

Answer 25

Curie

Roentgen

Question 26

Curie

Answer 26

3.7x10¹⁰ decay events/second

Question 27

Roentgen

Answer 27

2.58x10^-4 C of charge per kg

Question 28

REM

Answer 28

“roentgen equivalent man”

-human radiation exposure

20-100: decreased WBC count; cancer

100-400: radiation sickness, skin lesions, cancer

500: death

Question 29

Isotope Scanning

Answer 29

-radioactive isotope is introduced to the body and radiation emitted by the isotope is detected

Question 30

Radiotherapy

Answer 30

-gamma rays are focused on internal tumors to kill them