Gives some properties of alpha, beta and gamma radiation

Q1.(a)     Table 1 gives some properties of alpha, beta and gamma radiation.

	Table 1
	Radiation	Range in air	Effect of a magnetic field
	Alpha particle	................................	deflected a small amount
	Beta particle	about 1m	deflected a lot
	Gamma ray	unlimited	.........................................

(i)      Which one of the following describes an alpha particle?

Tick () one box.

	It is the same as the nucleus of a helium atom.
	It is an electron.
	It is a negative ion.

(1)

(ii)     Complete Table 1 by adding the missing information.

(2)

(b)     Table 2 gives information about four radioactive isotopes.

	Table 2
	Isotope	Type of radiation emitted	Half-life
	iridium-192	gamma ray	74 days
	polonium-210	alpha particle	138 days
	polonium-213	alpha particle	less than 1 second
	technetium-99	gamma ray	6 hours

Two isotopes of polonium are given in the table. In terms of particles in the nucleus:

(i)      how are these two isotopes the same

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(1)

(ii)     how are these two isotopes different?

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(1)



(c)     To monitor the blood flow through a patientߣs heart, a doctor injects the patient with a very small dose of technetium-99. The gamma radiation detected outside of the patient’s body allows the doctor to see if the heart is working correctly.

(i)      Explain why technetium-99 is more suitable for this use than polonium-210.

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(2)

(ii)     Explain why technetium-99 is more suitable for this use than iridium-192.

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(2)

(d)     Technetium-99 (Tc) is produced by the beta decay (β) of an isotope of molybdenum (Mo).

The decay can be represented by the equation below.

Complete the equation by writing the correct number in each of the two boxes.

 

(2)

(Total 11 marks)

(e)     When a thorium-230 nucleus decays, it emits radiation and changes into radium-226.

What type of radiation, alpha, beta or gamma, is emitted by thorium-230?

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Explain the reason for your answer.

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(3)

 M1.(a)      (i)     It is the same as the nucleus of a helium atom.

1

(ii)     (about) 5 cm

accept any number between 2 and 8 cm

1

not deflected

accept none

1

(b)     (i)     number of protons

accept same atomic / proton number

1

(ii)     numbers of neutrons

accept different mass numbers

1

(c)     (i)     because polonium-210 is an alpha emitter

1

and alpha particles cannot be detected outside bodyor alpha particles produce heavy ionisation

1

(ii)     because iridium-192 has a long(er) half life

1

and so will be radioactive for longer

1

(d)     99

1
42

1

[11]

 

(e)     alpha (particle)

reason may score even if beta or gamma is chosen

1

mass number goes down by 4or

number of protons and neutrons goes down by 4
or
number of neutrons goes down by 2

candidates that answer correctly in terms of why gamma and beta decay are not possible gain full credit

1

atomic / proton number goes down by 2or

number of protons goes down by 2

accept an alpha particle consists of 2 neutrons and 2 protons for 1 mark

accept alpha equals ⁴2He or ⁴2α for 1 mark

an alpha particle is a helium nucleus is insufficient for this mark

1

[8]

 

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