Radioactivity Part 1

Question 1

When was radioactivity discovered?

Answer 1

March 1, 1896

Question 2

Who discovered radioactivity?

Answer 2

Antoine Henri Becquerel

Question 3

French physicist who accidentally discovered radioactivity by opening a drawer

Answer 3

Antoine Henri Becquerel

Question 4

When was Antoine Becquerel born?

Answer 4

In Paris, 1852

Question 5

What did Antoine studied because of his father?

Answer 5

Fluorescence and Phosphorescence

Question 6

Becquerel was specially interested in what?

Answer 6

Uranium and its compounds

Question 7

Who is Antoine Henri Becquerel’s father?

Answer 7

Edmond Becquerel

Question 8

This is where Becquerel first heard about Roentgen’s theory.

Answer 8

French Academy of Sciences

Question 9

TRUE or FALSE: From Becquerel’s accidental discovery, uranium salts emitted radiation without any stimulation from sunlight.

Answer 9

True

Question 10

TRUE or FALSE: It was announced that Uranium was indeed what was emitting the radiation.

Answer 10

True

Question 11

They began studying the strange Uranium rays

Answer 11

Marie Sklodowska Curie and Pierre Curie

Question 12

When did the Curies started studying the strange Uranium rays?

Answer 12

1898

Question 13

What are the 3 radioactive elements discovered by the Curies?

Answer 13

1. Polonium (Po)
2. Thorium (Th)
3. Radium (Ra)

Question 14

What did the Curies mainly discovered?

Answer 14

They figured out how to measure the intensity of radioactivity

Question 15

Who coined the term “radioactivity”

Answer 15

Marie Curie

Question 16

Becquerel and the Curies shared what specific award, for their work in radioactivity?

Answer 16

1903 Nobel Prize

Question 17

This is a naturally-occurring phenomenon in a number of substances

Answer 17

Radioactivity

Question 18

This is where atoms of a substance spontaneously/continuously emit invisible but energetic radiations, which can penetrate materials that are opaque to visible light

Answer 18

Radioactivity

Question 19

Radioactivity can be harmful to living cells but can be helpful to the field of what?

Answer 19

Field of medicine

Question 20

TRUE or FALSE: Vast majority of nuclei found on Earth is not stable.

Answer 20

False, because most of nuclei found on Earth is indeed, stable.

Question 21

Approximate number of stable isotopes:

Answer 21

270 stable isotopes

Question 22

Number of naturally-occurring radioisotopes:

Answer 22

50 radioactive isotopes (radioisotopes)

Question 23

This is a plot of nuclei as a function of proton/atomic number (z) and neutron number (N) which includes all stable nuclei and known radioactive nuclei, either man-made or natural, along with their decay properties

Answer 23

Chart of nuclides

Question 24

TRUE or FALSE: Nuclei are unstable if they are excited, that is, not in their lowest energy states.

Answer 24

True

Question 25

"Nature seeks the lowest energy state"

Answer 25

Nuclear stability

Question 26

TRUE or FALSE: Things are most stable in their lowest energy state, while unstable atoms will try and become stable by getting to a lower energy state by emitting some form of radioactivity

Answer 26

True

Question 27

What are the 3 forces that works in the nucleus in holding or not holding protons?

Answer 27

1. Electromagnetic forces 2. Strong force 3. Weak force

Question 28

A type of force wherein it follows the principle of like charges repel ; positive charges of protons tend to force the protons apart

Answer 28

Electromagnetic force

Question 29

This type of force counters EM force ; attracts protons to each other

Answer 29

Strong force

Question 30

This force governs how an unstable nucleus will decay into a stable nucleus

Answer 30

Weak force

Question 31

This is a successful way in predicting nuclear stability

Answer 31

Neutron-to-proton ratio (n/p)

Question 32

TRUE or FALSE: N/P ratio is close to 1 for atoms of elements with low atomic numbers (less than 20 protons)

Answer 32

True

Question 33

TRUE or FALSE: element 84 and beyond is unstable.

Answer 33

True

Question 33

TRUE or FALSE: N/P ratio increases as the atomic number increases past element 20 (Calcium) to 84 (Polonium)

Answer 33

True

Question 34

This particle of an atom helps in binding the nucleus together

Answer 34

Neutrons

Question 35

Whether a nucleus contains an odd/even number of protons and neutrons

Answer 35

Predicting Nuclear Stability

Question 36

Choose from the two choices in the parenthesis: Nuclides containing odd numbers of both protons and neutrons are (more , less) stable and more radioactive.

Answer 36

Less

Question 37

TRUE or FALSE: Nuclides containing even numbers of both protons and neutrons are most stable.

Answer 37

True

Question 38

TRUE or FALSE: Greater binding energy means a more stable nucleus.

Answer 38

True

Question 39

This is a plot of the number of neutrons vs the number of protons for stable nuclei reveals that the stable isotopes fall into a narrow band.

Answer 39

Belt of Stability or Band of Stability

Question 40

This is a property exhibited by certain types of matter emitting energy and subatomic particles spontaneously

Answer 40

Radioactivity

Question 41

TRUE or FALSE: Unstable nucleus will decompose spontaneously, or decay, into a more stable configuration.

Answer 41

True

Question 42

What are the 2 main sources of radioactivity?

Answer 42

1. Natural environmental sources 2. Artificial sources

Question 43

This originates in outer space continuously bombarded the Earth's gaseous envelope

Answer 43

Cosmic rays

Question 44

These include long-lived radioactive elements such as uranium, thorium, and any of their decay product, such as radium and radon.

Answer 44

Terrestrial sources

Question 45

These are products of nuclear reaction initiated by man

Answer 45

Artificial sources

Question 46

These are designed to produce power, neutrons, radioisotopes, and fissile materials

Answer 46

Nuclear reactors

Question 47

This is the primary source of radiation from the human body

Answer 47

Potassium-40 (40K)

Question 48

2 reasons why potassium is the primary source of radiation from the human body:

Answer 48

1. Present in all the tissues in the body 2. Easy to digest

Question 49

This is the number of times a radioactive decay occurs in the sample per unit time

Answer 49

Activity (decay rate)

Question 50

TRUE or FALSE: Activity of a radioactive sample decreases with time

Answer 50

True

Question 51

1 Bq = ? dps

Answer 51

1 dps

Question 52

1 Ci = ? dps

Answer 52

3.7 x 10^10 dps

Question 53

1 Ci = ? Bq

Answer 53

3.7 x 10^10 Bq

Question 54

1 Bq = ? Ci

Answer 54

2.7 x 10^-11 Ci

Question 55

1 mci = ? Ci

Answer 55

0.0001 Ci or 1x10^-3 Ci

Question 56

1 μci = ? Ci

Answer 56

0.000001 Ci or 1x10^-6 Ci

Question 57

This is the activity per unit mass of a substance, whether atoms of a single nuclide or a compound

Answer 57

Specific activity

Question 58

unit of specific activity:

Answer 58

Bq/kg (SI unit), Ci/g, or dpm/g

Question 59

This is the amount of time it takes for the decay rate to reach half of its original value

Answer 59

Half-life (t 1/2)

Question 60

Types of half-life:

Answer 60

1. Physical Half-Life 2. Biological Half-life 3. Effective Half-life

Question 61

Period of time required to reduce the radioactivity level to a source to exactly one half of its original value.

Answer 61

Physical half-life

Question 62

This reduces the amount of drug/pharmaceutical in an organ or the body to exactly one half of its original value.

Answer 62

Biological half-life

Question 63

This reduces the radioactivity level of an internal organ or the whole body to exactly one half of its original value.

Answer 63

Effective half-life