Nuclear Chemistry

Question 1

Radioactivity

Answer 1

Emission of subatomic particles or high energy electromagnetic radiation by nuclei – such atoms/isotopes said to be radioactive

Question 2

Nuclear chemistry discovered by??

Answer 2

Becquerel –called strange, new emissions uranic Rays (emitted from uranium)

Question 3

Marie curie

Answer 3

Discovered Po & Ra – emitted uranic Rays

Question 4

Types of radioactivity

Answer 4

• Alpha
• beta
• electron capture
• gamma Ray emission
• positron emission

Question 5

Nucleus

Answer 5

Comprised of two nucleons

Question 6

Nucleons

Answer 6

Protons & neutrons

Anything inside the nucleus

Question 7

Isotopes

Answer 7

An atom with the same number of protons but with a diff number of neutrons I.e. Uranium -234

Question 8

Radioisotopes

Answer 8

An isotope of any element that is unstable & therefore radioactive– this instability comes from an unstable proton to neutron ratio

Question 9

Transmutation

Answer 9

Changing the nucleus of one element into the nuclei of a different element

Question 10

Transmutation facts

Answer 10

• all elements above atomic number 83 are radioactive
• to determine how a radioactive isotope normally decay
• when writing a transmutation (nuclear) equation, it is necessary to balance the mass number & atomic number

Question 11

Natural transmutation

Answer 11

Processes always have JUST ONE REACTANT (with the exception of electron capture)

Question 12

Alpha particle (a)

Answer 12

2protons and 2 neutrons
Same composition as He nucleus (4/2 He)
Charge of an alpha particle is 2+ due to the prescience of the 2 protons

Question 13

*never look at mass on periodic table *

Answer 13

.

Question 14

Beta particle (b)

Answer 14

Very fast moving electron that has been emitted from a neutron of an unstable nucleus - this occurs when a neutron falls apart into a proton and an electron (0/-1 B) - the -1 subscript denotes the negative charge of the particle

Question 15

Positron emission

Answer 15

Radioactive decay process that involves the emission of a positron from a nucleus– this occurs when a proton is converted to a neutron and a positron

Question 16

Electron capture

Answer 16

Other common radioactive decay process that decreased the number of protons – occurs when a proton combines with a proton to form a neutron

Question 17

Gamma rays

Answer 17

High energy photons electromagnetic radiation (0/0 y) both subscript & superscript are 0 –> thus the emission of gamma rays do not change the atomic number or mass number

Question 18

2 0/0 y

What is the 2?

Answer 18

The 2 in front of the y symbol indicates that two gamma Rays of different frequencies are emitted

Question 19

Relative penetration of radiation

Answer 19

A particles - blocked by paper & skin
B particles - blocked by wood, metal, & a little bit of skin (~1 cm)
Y Rays - blocked by lead but not by human skin

Question 20

Radioactive series

Answer 20

Large radioactive nuclei cannot stabilize by undergoing only one nuclear transformation– they undergo a series of decays in the form a stable nuclide

Question 21

Ionizing radiation

Answer 21

Radiation with enough energy so that with a interaction with an atom can remove the electron(s) from the orbit causing the atom to become charged

Question 22

Neutron- protons ratio

Answer 22

Any element with more than 1 proton will have repulsion bet. protons I the nucleus – a strong nuclear force helps keep the nucleus from flying apart – for a smaller nuclei (z

Question 23

Z

Answer 23

Atomic number

Question 24

Belt of stability

Answer 24

Shaded region shows what nuclide would be stable

Question 25

Nuclei above the belt

Answer 25

Have too many neutrons -- emit beta particles

Question 26

Nuclei below the belt

Answer 26

Have too many protons --positron emission or electron capture

Question 27

Stable nuclei

Answer 27

There are no stable nuclei with an atomic number above 83 -- tend to decay by alpha emission

Question 28

Natural transmission #2

Answer 28

Only 1 reactant | Occurs when radioactive elements spontaneously decay over time & transform into other more stable elements

Question 29

Artificial transmutation

Answer 29

2+ reactants Occurs when scientist intentionally bombard the nucleus with high energy particles Used to generate energy in atomic bombs & power plants

Question 30

Nuclear transformations

Answer 30

Can be induced by accelerating a particle & colliding it with the nuclide --these particles accelerators are enormous , having circular tracks with radii that are miles long

Question 31

Nuclear fission

Answer 31

Splitting nucleus ink fragments - releases large amounts of energy - chain reaction

Question 32

Critical mass

Answer 32

Starting amount of mass to sustain the nuclear fission

Question 33

Mass to energy

Answer 33

E=mc^2 | Explains relationship bet energy formation and matter loss

Question 34

Mass defect

Answer 34

Amount by which the mass of an atomic nucleus is less than the sum of the mass of its particles (mass products

Question 35

Nuclear binding energy

Answer 35

Energy corresponding to mass defect -- amount of energy required to break apart nucleus into nucleons

Question 36

Defense in depth

Answer 36

48" concrete containment building 35" concrete shield 8" steel reactor vessel Solid nuclear fuel inside steel tubes

Question 37

Meltdown

Answer 37

Melting of a significant proton of a nuclear reactor core due to inadequate cooling of the fuel elements --- a condition that could lead to the escape of radiation

Question 38

Half life

Answer 38

The amount of time it takes for half of the substance to decay

Question 39

Used fuel

Answer 39

Once the reaction occurs, the uranium is stored in cold pools

Question 40

Dry cask

Answer 40

A concrete containment for permanent storing underground - similar to a mine

Question 41

Pros of nuclear power

Answer 41

High amounts of energy 1 million X as much energy in 1 lb of uranium as on 1lb of coal Emission free Prevents large amounts of greenhouse gasses

Question 42

Cons of nuclear power

Answer 42

``` Meltdown (Chernobyl) Increased risk of cancer Birth defects Reduced immunity Genetic damage / mutations Effects wildlife Decreasing biodiversity ```

Question 43

Nuclear fusion

Answer 43

The combining of atomic nuclei - occurs on the sun where hydrogen atoms fuse to form helium atoms

Question 44

Thermonuclear reactions

Answer 44

Fusions rations can release very large amounts of energy, but can require extremely high temp. & pressures

Question 45

Nuclear chemistry

Answer 45

The study of the structure of atomic nuclei and the changes they undergo