Atomic Physics

Question 1

Alpha particles, α-particles

4 attributes

(2)

structure

path of movement

Answer 1

Double positive charge
Helium nucleus
Stopped by paper
Highest ionization potential (ability to attract electrons from other elements)

(particle, slow)

4
α
2

curved path (with north up top) towards north and into page

Question 2

Beta-particles, β-particles

Answer 2

Single negative charge
Fast moving electrons
Stopped by aluminum
Less ionization potential (ability to attract electrons from other elements)

(particle, fast)

0
β
-1

curved path (with north up top) towards south and out of page

Question 3

Gamma-particles, γ-rays

Answer 3

No charge
Electromagnetic radiation
Only stopped by thick a sheet of lead
Least ionization potential (ability to attract electrons from other elements)

(wave, speed of light)

0
γ
0

Question 4

Half-life

Answer 4

Time in which the activity or mass of substance becomes half

Question 5

Atomic symbol

Answer 5

A
X
Z

A is the total number of protons and neutrons
Z is the total number of protons which is the number of electrons to
A - Z gives the number of neutrons

Question 6

Isotopes, examples and uses

Answer 6

Same number of protons but different number of
neutrons

Examples of common isotopes:

• Hydrogen
• Deuterium
• Tritium

1) Isotopes of iodine are used for radiotherapy in treatment of hyperthyroidism, cancer, etc.
2) Uranium, Radium, Polonium isotopes are used in atomic reactors.
3) Cobalt isotopes are used for irradiation of food products.

Question 7

Radioactive decay

Answer 7

Radioactive decay is the process by which an unstable atomic nucleus (too many protons or wrong mix of particles in nucleus) loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha decay, beta decay, and gamma decay, all of which involve emitting one or more particles.

Radioactive decay is essentially considered breaking down, getting rid of some matter or energy as a result of the nucleus releasing α or β particles or γ rays.

Question 8

When, where and why do radioactive emissions occur

how to detect

Answer 8

They occur randomly over space and time and as a result of unstable nucleus decay

Geiger muller tube detects radioactivity as well as electric and magnetic fields that separate different types of radiation.

Question 9

How to safely store and handle radioactive material

Answer 9

• Store the sources in lead-lined boxes and keep at a distance from people
• Minimise the amount of time you handle sources for and return them to their boxes as soon as you have finished using them
• During use, keep yourself (and other people) as far from the sources as feasible. When handling the sources do so at arm’s length, using a pair of tongs

Question 10

Rutherford Experiment

Answer 10

• beams of alpha particles ( α - particles) shot from radioactive source at thin gold foil sheet
• fluorescent screen surrounding gold foil
• most particles went through, some deflected and very few reflected back
• small concentrated mass in atom to make particles get reflected, evidence of nucleus
• α particles deflected by gold nucleus states nucleus has positive charge, both positive hence deflection
• many particles that passed through shows atom is mainly made of empty space
• closer particle is to beam, greater deflection

Question 11

Uses of radioactivity

Answer 11

• Radiotherapy
• Sterilisation
• Archaeology