chapter 4

Question 1

What makes a stable nuclei

Answer 1

the force of attraction and repulsion are balanced

Question 2

which elements usually have a stable nuclei, and which don’t

Answer 2

element below atomic number #19 usually have a stable nuclei, elements atomic number #20 and above usually don’t have stable nuclei

Question 3

what makes a nuclei unstable?

Answer 3

too many or too few protons compared to number of neutrons therefore the forces are unbalanced

Question 4

Radiation

Answer 4

energy emitted by unstable nuclei to become more stable

Question 5

radioisotopes

Answer 5

isotopes that emits radiation

Question 6

Transmutation

Answer 6

change in number of protons in nucleus (atom of an element converted to a different element)

Question 7

Which elements are produced artificially?

Answer 7

elements #93 or higher on the periodic table are produced in nuclear labs

Question 8

How does emitting radiation help atoms be more stable?

Answer 8

an unstable nucleus forms a more stable, lower energy nucleus

Question 9

What are the types of radiation?

Answer 9

alpha particles, beta particles, positron, Gamma rays

Question 10

Alpha particles

Answer 10

identical to helium nucleus (2 protons, 2 neutrons, mass number 4, atomic number 2, charge of 2+

Question 11

beta particles

Answer 11

high energy electron with a charge of 1-, mass number 0

Question 12

when do beta particles form?

Answer 12

when a neutron in an unstable nucleus changes to a proton and an electron.

Question 13

positron

Answer 13

positive 1+ charge with a mass of 0, it is an antimatter

Question 14

when is a positron produced?

Answer 14

it is produced by the unstable nucleus when a proton is transformed into a neutron and a positron

Question 15

How are gamma rays produced?

Answer 15

when a positron and an electron collides

Question 16

ionization radiation

Answer 16

when radiation hits molecules in its way, electrons may be knocked away forming unstable ions

Question 17

why is ionization energy harmful for humans

Answer 17

if it passes through human body, it might interact with water molecules removing electrons and producing H20+

Question 18

Which type of cells are most sensitive to ionization radiation? and examples?

Answer 18

cells that undergo rapid cell division, such as bone marrow, skin, reproductive organs, cells of growing children and cancer cells

Question 19

shielding

Answer 19

materials used to provide protection from radioactive sources

Question 20

Alpha particles protection?

Answer 20

paper, skin, clothing

Question 21

how do alpha particles travel?

Answer 21

in the air for a few cm before they collide with air molecules , acquire electrons and become helium

Question 22

Beta particle shielding

Answer 22

heavy clothes such as lab coats and gloves

Question 23

which radiation particle has the largest mass?

Answer 23

alpha particles

Question 24

Gamma rays protection

Answer 24

only dense shielding such as concrete and lead.

Question 25

how far can gamma rays travel?

Answer 25

through bodies

Question 26

How does one protect self from radiation?

Answer 26

greater distance from radioactive source and less exposure/time with radioactive source

Question 27

What happens during radioactive decay?

Answer 27

unstable nucleus breaks down and releases high energy radiation

Question 28

equation of a nuclear reaction:

Answer 28

Radioactive nucleus-->new nucleus + radiation

Question 29

What happens to a radioactive nucleus during an alpha decay reaction?

Answer 29

The mass of the nucleus goes down by 4 and atomic number (protons) goes down by 2.

Question 30

What happens to a radioactive nucleus during a beta decay?

Answer 30

the mass stays the same, the atomic number (protons) increases by 1.

Question 31

What happens to a radioactive nucleus during a positron emission

Answer 31

mass number stays the same, the atomic number (protons) goes down by 1

Question 32

What happens to a radioactive nucleus during a gamma emission?

Answer 32

the mass number and atomic number stays the same.

Question 33

Most common source of alpha particle

Answer 33

Radium-226

Question 34

most common source of beta particle

Answer 34

carbon-14

Question 35

most common source of gamma particle

Answer 35

Technetium-99m

Question 36

why are pure gamma emissions rare?

Answer 36

they accompany most alpha and beta radiation

Question 37

transmutation

Answer 37

converting stable nonradioactive isotopes into radioactive ones

Question 38

What is different about all atomic numbers 92 and above? and how?

Answer 38

they are created in labs through transmutation by bombarding high speed particles (protons, neutrons and small nuclei) and when absorbed by stable nucleus, radioactive isotopes are created.

Question 39

How and why is Technetium-99m used in nuclear medicine?

Answer 39

for diagnostic purposes (brain tumors, spleen and liver examinations) since they pass through the body

Question 40

Geiger counter

Answer 40

instrument for measuring radiation (beta and gamma)

Question 41

what unit measures disintegration per second of radiation?

Answer 41

Curie (c) | becquerel (Bq) (SI UNIT)

Question 42

curie (c)

Answer 42

3.7 x 10^10 disintergrations per second

Question 43

becquerel (Bq)

Answer 43

1 disintegration per second

Question 44

what is disintegration?

Answer 44

activity of sample (radiation)

Question 45

what unit measures amount of radiation absorbed by a g of a material?

Answer 45

rad (radiation absorbed dose) | Gray (Gy) (SI UNIT)

Question 46

1 Gy= ___rad

Answer 46

1 Gy= 100 rad

Question 47

what unit measures the biological effects of different kinds of radiation?

Answer 47

rem (radiation equivalent in humans) | sievert (sv) (SI UNIT)

Question 48

formula to calculate rem?

Answer 48

biological damage (rem)= absorbed dose (rad) x factor (of radiation)

Question 49

``` what is the factor of: gamma particles: beta particles: protons: neutrons: alpha particles: ```

Answer 49

Gamma, beta: 1 high energy proton, neutron: 10 alpha: 20

Question 50

1 sv= __rem | 1 rem=__ mrem

Answer 50

1 sv= 100rem | 1 rem= 1000 mrem

Question 51

how much radiation does an average person in the US get annually?

Answer 51

360 mrem /year

Question 52

How does a geiger counter measure radiation?

Answer 52

uses ions produced by radiation to create an electrical current

Question 53

why is radiation used in medicine?

Answer 53

they have short half lives

Question 54

how much radiation is considered undetected on body?

Answer 54

25 rem

Question 55

LD-50

Answer 55

lethal dose of radiation

Question 56

Fission

Answer 56

Large nucleus split into smaller pieces releasing energy

Question 57

Process of fission

Answer 57

Releases neutrons and large amounts of gamma radiation and energy 1. Neutron collides with nucleus (of uranium) 2. Nucleus becomes unstable and splits into smaller nuclei

Question 58

Chain reaction

Answer 58

Fission reaction that will continue once initiated by high energy neutron bombarding a heavy nucleus

Question 59

Fusion

Answer 59

2 small nuclei combine to form a larger nucleus

Question 60

Is mass lost during fusion?

Answer 60

Yes, more energy is lost than fission

Question 61

Why is fusion uncommon?

Answer 61

It requires the temperature of 100,000,000 C for hydrogen nuclei to undergo fusion