Stable and unstable nuclei

Question 1

Which interaction is responsible for decay in the nucleus?

Answer 1

The weak interaction.

Question 2

What force holds the atom together?

Answer 2

The strong force

Question 3

What are the three main forces acting in the nucleus?

Answer 3

1) Electromagnetic force- causes the positively charged protons in the nucleus to repel 2) Gravitational- attraction between nucleons due to mass 3) Strong nuclear- mainly attractive force that holds the nucleus together

Question 4

Name the four fundamental forces.

Answer 4

Gravity, Electromagnetic force, Strong nuclear force, Weak nuclear force

Question 5

What force is responsible for keeping the nucleus together?

Answer 5

Strong nuclear force

Question 6

Which type of particles experience the strong nuclear force?

Answer 6

Hadrons (mesons & barions) but leptons do not

Question 7

What is the short range attraction of the strong nuclear force?

Answer 7

3 x 10-15m (or 3 femtometers)

Question 8

What is the short range repulsion of the strong nuclear force?

Answer 8

0.5 x 10-15m (or 0.5 femtometers)

Question 9

How does the strong nuclear force change at different nucleon separations?

Answer 9

Repulsive for very small separations- up to 0.5 fm Attractive up to 3fm After 3 fm - falls towards 0

Question 10

What is fm metres?

Answer 10

1fm=1*10^15

Question 11

What are alpha particles?

Answer 11

2 protons and 2 neutrons (helium nucleus)

Question 12

What are beta particles?

Answer 12

A high speed electron

Question 13

Up to what distance is the strong force repulsive? Give the unit as well.

Answer 13

0.5fm

Question 14

In what range is the strong force attractive? Give the unit as well.

Answer 14

0.5-4fm

Question 15

What two words describe radioactive decay? (They begin with R and S)

Answer 15

Random and spontaneous

Question 16

Why do atoms decay?

Answer 16

To become stable.

Question 17

Can atoms decay more than once to become stable?

Answer 17

Yes!

Question 18

What is alpha decay?

Answer 18

2 protons and 2 neutrons

Question 19

What is beta decay?

Answer 19

A fast moving electron.

Question 20

What does a neutron split to become in Beta minus decay?

Answer 20

A proton, electron and antineutrino.

Question 21

What happens to the proton, nucleon and neutron number in Beta minus decay?

Answer 21

Proton Number: increases by one. Neutron number: falls by one. Nucleon number: stays the same.

Question 22

What is the role of the anti neutrino in Beta minus decay?

Answer 22

To conserve momentum.

Question 23

What properties belong to the neutrino?

Answer 23

• No charge - Not affected by electrostatic force - Tiny mass - Millions pass through your body every second!

Question 24

What is gamma?

Answer 24

A photon of energy

Question 25

What properties does gamma have?

Answer 25

• Zero charge -Zero mass

Question 26

What is the purpose of gamma?

Answer 26

It is released to channel energy away from an excited nucleus.

Question 27

What are gamma rays?

Answer 27

Photons

Question 28

Which particles are emitted in beta-plus decay?

Answer 28

A neutron, a positron and an electron neutrino.

Question 29

What are the three types of nuclear decay?

Answer 29

Alpha, beta and gamma decay.

Question 30

What is the equation for alpha decay?

Answer 30

Question 31

What is the equation for beta decay?

Answer 31