Nuclear Structure & Decay

Question 1

Higher Z elements are relative more neurton rich or proton rich?

Answer 1

neutron rich

Question 2

Which nuclei Z of elements are unstable and has no stable form?

Answer 2

Nuclei with Z > 83

Question 3

What is an example of beta minus decay?

Answer 3

32P –> 32S (Z of P is 15 and becomes 16 and then P turns into S)

Question 4

Does Beta-minus decay happen to neutron-rich or neutron-poor?

Answer 4

Neutron-rich

Question 5

Does Beta-plus decay happen to neutron-rich or neutron-poor?

Answer 5

Neutron-poor

Question 6

Draw the types of decay with x-axis is the # of protons and y-axis is the # of neutrons

Answer 6

Question 7

beta minus decay takes place for isotopes that are relatively neutron-rich. How are they made?

Answer 7

In a nuclear reactor

Question 8

beta plus decay takes place for isotopes that are relatively neutron-poor. How are they made?

Answer 8

They are produced in cyclotrons where a target is bombarded with a heavy charged particle such as a proton.

Question 9

Give a specific exampl of beta plus decay

Answer 9

18F –> 18O + B+ (positron)

Question 10

What nuclei undergo alpha decay?

Answer 10

particularly heavy ones

Question 11

What other decay modes are there (other than beta, alpha decay)?

Answer 11

• electron capture
• isomeric transition
• internal conversion

Question 12

What is electron capture?

Answer 12

an inner-shell electron interacts witht the nucleus and the result is that a proton is lost.

Question 13

Provide a specific example of electorn capture?

Answer 13

125I –> 125mTe (tellurium in a metastable state)

Question 14

What is isomeric conversion?

Answer 14

Transition in which a nucleus in an excited state transitions to the ground state and a photon is emitted.

There is no change in Z.

Question 15

What happens in the electron capture specfiically with 125 I?

Answer 15

125 I (iodine) decays into 125mTe (tellurium) in a metastable state, which is a high energy state of the nucleus that lasts for a long time but eventually decays into a ground state.

Question 16

After an electron capture, what happens?

Answer 16

There is a vacancy in an inner shell electron and an outer shell electron can transition into this state, producing a characteristic photon.

Auger electron can also be emitted.

Question 17

Describe the below parameters in electron capture

1) Z
2) Types of particles emitted

Answer 17

Z decreases (since a proton is lost by interacting with an electron)

Types of particles emitted: gamma ray, Auger electrons, Alpha particle

Question 18

What happens to Z value in beta-minus decay?

Answer 18

Z increases (consider both electron and proton are lost and proton is being added to the nucleus)

Question 19

What happens to Z value in beta-plus decay?

Answer 19

Z decreases

Question 20

How does Z value chance in alpha decay?

Answer 20

Z –> Z-4 ?

Question 21

What is internal conversion?

Answer 21

Conversion in which an excited nucleus transitions to the ground satate, however, instead of emitting a photon, an electron is ejected.

The energy of the ejected electron is the energy of the transition (which would have been a photon) minus the binding energy of the electron.

There is no change in Z.

Question 22

How does Z value changen in isomeric transition?

Answer 22

No change

Question 23

How does Z value changen in internal conversion?

Answer 23

No change in Z.

Question 24

What are the main particles emitted in isometric transition?

Answer 24

Gamma ray in the form of photon

Question 25

What are the main particles emitted in internal conversion?

Answer 25

Gamma ray (in form of ejected electron)

Question 26

Describe the two types of equilibrium of isotopes

Answer 26

Secular and Transient Equilibrium.