physics - chapter 5 (radioactive materials

atomic structure

atomic structure

Positively charged nucleus that contains neutrons and protons, surrounded by negatively charged electrons

radius of atom

1x10^-10

radious of nucleus

10,000 times smaller than atom/ very small

relative mass of electron

very small

relative mass of proton

1

relative mass of neutron

1

relative charge of electron

-1

relative charge of neutron

0

relative charge of proton

+1

Dalton - atomic model

• everything made out of tiny spheres

• spheres could not be divided

JJ Thompson

plum pudding model

• discovered the electron

• spheres of positive matter

• tiny negative electrons placed all throughout atom

Rutheford

gold foil experiment

• particles went straight through = lot of empty space in atom

• some particles displaced = nucleus had to be positively charged

alpha

• highly ionising

• weakly penetrating

• helium nucleus

beta

• electron

• medium ionising

• medium penetrating

gamma

• radiation

• low ionising

• highly penetrating

alpha decay

• mass decreases 4

• charge of nucleus decreases 2

beta decay

• mass stays the same

• charge of nucleus will increase 1

gamma decay

• mass stays the same

• charge stays the same

contamination

• lasts long amount of time

irradiation

• lasts for a short period of time

• does NOT make objects radiation

chemotherapy

• gamma rays are emitted

• absorbs the energy of cancerous cells and dies

• hard to direct accurately so healthy cells may be irradiated

• can have unhealthy side effects

smoke alarms

• alpha emitter

• half life of 432 years

• when smoke reaches alarm amount of alpha particles drop

• causing alarm to go

• weak activity so not harmful to anyone