Radioactivity Flashcards

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1
Q

Define ‘radiation’

A

Transmission of radiant energy

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2
Q

Define ‘radioactivity’

A

Spontaneous emission of radiation from an atom, in order to form a more stable configuration

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3
Q

Define ‘isotope’ (of an element)

A

An atom with the same atomic number (Z) of the given element, but different mass number (A)/number of neutrons

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4
Q

Define ‘half-life’

A

The time taken for the activity of a radioactive substance to fall by half

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5
Q

Describe alpha decay and its effects on an atom

A

Alpha decay is the emission of a helium nucleus (2 protons and 4 neutrons) by a radioactive atom

It decreases the atomic number (Z) by 2 and mass number (A) by 4

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6
Q

Describe positron emission and its effects on an atom

A

Positron emission is the emission of the positively charged component of a proton (positron) to form a neutron

This decreases atomic number (Z) by 1, but mass number (A) remains unchanged

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7
Q

Describe beta decay and its effect on an atom

A

Beta decay is the emission of a negatively charged electron from a neutron to form a proton

This increases the atomic number (Z) by 1, whilst the mass number (A) is unaffected.

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8
Q

What conditions cause positron emission?

A

A neutron deficit, to create more neutrons to compensate

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9
Q

What conditions causes beta decay?

A

A neutron abundance, to decrease the number of neutrons in the nucleus

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10
Q

When does gamma decay occur?

A

Gamma rays are released due to a nucleus being in a metastable state and are emitted stablise it.

They’re usually released as a result of other radioactive decay too.

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11
Q

Describe gamma decay and its effect on an atom

A

A gamma ray photon is emitted to release energy from an excited nucleus (metastable). No particles are emitted so the atomic make-up is unaffected.

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12
Q

A carbon (Z=6, A=12) atom undergoes alpha decay - what is the result?

A

A new atom with Z=4 and A=8 is created (Berylium)

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13
Q

An oxygen atom (Z=8, A=16) undergoes alpha decay - what is the result?

A

A new atom with Z=6 and A=12) is created (Carbon)

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14
Q

What constitutes ‘ionising’ radiation?

A

Ionising radiation has enough energy to eject an electron from a target, resulting in ion formation

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15
Q

Name 3 natural sources of radiation, with examples

A

Cosmic Radiation - solar flares from the sun
Terrastial radiation - radiation from radon, granite and uranium
Internal - ingested radiation from bananas, brazil nuts and carbon-14

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16
Q

Name a source of man-made ionising radiation

A

X-rays produced from an x-ray tube

17
Q

Which 2 groups are likely to be exposed to man-made radiation?

A
  • Occupationally exposed (radiographers)

- Patients of radiology