Atomic structure

Question 1

Radioactivity

Answer 1

To become stable the nuclease gives out radiation
and it is random
*Activity is the rate at which a source of unstable nuclei decay 1Bq=1 decay per second
*Count-rate is the number of decays recorded each second by a detector(Geiger muller tube)

Question 2

Alpha

Answer 2

• 2 protons 2 neutron same as helium nuclease
• Can be stopped by a single sheet of paper
• Strongly ionising
• High likely to be absorbed and cause damage

Question 3

Beta

Answer 3

• A high-speed electron
• Ejected from the nuclease as a neutron turns into a proton
• Stopped by a few mm of aluminium
• Quite strongly ionising
• Can penetrate the body to inner organs & can cause damage if absorbed

Question 4

Gamma

Answer 4

• Type of em radiation
• Emitted from nuclease
• Stopped by several cm of lead
• Weakly ionising
• Likely to pass through living cells without being absorbed

Question 5

IRRADIATION

Answer 5

IRRADIATION
*Exposing an object to nuclear radiation
*When irradiated it does not emit radiation
*Gloves can be worn to protect against alpha radiation
A lead apron or lead walls and lead glass screen to stop beta and gamma

Question 6

Radioactive contamination

Answer 6

*Unwanted radioactive isotopes end up on other material this is called contamination
*Hazardous as they decay and emit ionising radiation
*If inhaled by dust or swallowed by food its dangerous it would not be harmful unless entered.(Alpha)
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Question 7

Half-life

Answer 7

Half life of a radioactive isotope is the time it takes for the number of nuclei of the isotope in a sample to halve
Half life is also the time it take for the count rate from a sample containing the isotope to fall to half its initial level