Atomic and Nuclear

Question 1

What did Thomson discover and what was his model.

Answer 1

He discovered electons (- charge) coming from a neutral atom.
evenly spread positiveness with electrons sprinkled throughout.

Question 2

List the Alpha particles definition, penetrating ability and ionisation ability

Answer 2

helium nuclei, few cm in air, stopped by paper, most ionising

Question 3

List the Beta particles definition, penetrating ability and ionisation ability

Answer 3

high-speed electron, stopped by Al (med pen ability), med ionisation

Question 4

List the Gamma particles definition, penetrating ability and ionisation ability

Answer 4

Electromagnetic wave (photon), stopped by Pb (high), little to no ionisation

Question 5

Define

Ionisation

Answer 5

The process in which an electron is given enough energy to break away from an atom.

Question 6

Define

Fission

Answer 6

the process of a large atom splitting into fission fragments

Question 7

When can fission occur?

Answer 7

• It can be induced in reactor or bomb
• or can occur naturally

Question 8

What is the process of fission?

Answer 8

1. A neutron is added to a large nucleus
2. The nucleus becomes unstable
3. The nucleus splits into two fission fragments, 2-3 neutrons. Energy is released due to a loss of mass.

Question 9

What is a Chain Reaction

Answer 9

Occurs when the neutron emmited from a fissioning nucleus hits a new nucleus causing it to fission.

Question 10

List

the three observations of the Alpha Scattering Experiment

Answer 10

1. The majority of alpha particles passed straight through
2. Some were scattered at large angles
3. A very small number (1 in 8000) were deflected by more than 90 degrees - they bounced back

Question 11

What did the first observation mean?

The majority of alpha particles passed straight through

Answer 11

The atom was mostly empty space as the + charge must be significantly smaller than the atom for the particle to not have experienced e-static repulsion with it

Question 12

What did the second observation mean?

Some were scattered at large angles

Answer 12

Their must be a concentrated + charge in the nucleus to cause the particle to be deflected because of E-static force

Question 13

What did the third observation mean?

A very small number (1 in 8000) were deflected by more than 90 degrees

Answer 13

The particle must have encountered a + charge with a very large mass.

Question 14

Define

Fusion

Answer 14

the process of lighter nuclei fusing into heavier nuclei

Question 15

What does fusion need and why?

Answer 15

Fusion needs very high temperatures and pressure to have a lot of kinetic energy so that they can overcome the e-static repulsion due to the fact that they are both +.

Question 16

Define

Isotope

Answer 16

An atom with the same atomic number but a different mass number (therefore different stability)

Question 17

Define

Isotope

Answer 17

An atom with the same atomic number but a different mass number (therefore different stability)

Question 18

Define

Radioactive Decay

Answer 18

Some atoms are unstable (they cannot stay in their current arrangement) and therfore emit energy/particles (known as radiation) to remain stable.

Question 19

Define

Half-life

Answer 19

The time it takes for an radioactive sample to lose half of its mass.

Question 20

Is decay effected by heat?

Answer 20

No, it is random.

Question 21

What do fusion and fission both release?

Answer 21

Large amounts of energy due to a miniscule amount of mass loss.