Nuclear Chemistry Flashcards
1
Q
weight distribution of subatomic particles
A
protons and neutrons are both about 1840 time heavier than electrons
2
Q
history of the atomic model
A
1803 - solid sphere model
1904 - plum pudding model
1911 - nuclear model
1913 - planetary model
1926 - quantum model
3
Q
radiation
A
the process of emitting energy in the form of waves or particles (when radiation is spontaneous = nuclear decay)
4
Q
nuclear theory in atoms
A
- stable nucleus - nuclear force balances the repulsive force between protons
- as atomic mass increases - elements less stable
- after bismuth (83) every element is radioactive
- many isotopes are radioactive (radioisotopes)
5
Q
unstable nuclei decay
A
break down and release radiation for nucleus stability when releasing particles and energy
6
Q
types of radioactivity
A
- all are ionising (interact with atoms and dislodge electrons)
- Alpha emission
- Beta emission
- Gamma
7
Q
how is radiation characterised
A
- composition
- mass
- charge
- ionising power
- penetrating power
8
Q
alpha emission
A
- elements over 83
- release of alpha particles (2 proton 2 neutron) (identical to a helium nucleus)
- resulting nucleus may still be radioactive
- highly ionising due to their size
- deflected by magnetic and electric fields
- easier to stop and travel slower and less far
9
Q
beta emission
A
- occurs owing to excess of neutrons
- release of an electron from the nucleus
- neutron decays into a proton and electron, proton stays and electron is ejected
- moderately ionising
- stopped by small amount of metal
- move at almost any speed
- deflected by magnetic and electric fields
10
Q
gamma emission
A
- extremely high frequency of electromagnetic radiation
- often accompanies other types of radioactive decay
- allows atom to reach a lower energy state
- no change in the atoms atomic mass/mass no.s
11
Q
properties of gamma emission
A
- weakly ionising
- no charge, aren’t affected by magnetic and electric fields
- highly penetrating
- travel at speed of light
12
Q
effects of ionising radiation
A
- can kill or change the nature of living cells
- can be severe and immediate or not evident for long periods
13
Q
measuring severity of radiation
A
- type of radiation
- tissue or organ that absorbs it
- total amount absorbed or length of exposure
14
Q
uses of radioactivity
A
- medical scanning
- nuclear power
- cancer treatment
- carbon and rock dating
15
Q
nuclear power
A
- nuclear energy - the force that binds the nucleus together
- nuclear fission - nuclear energy released by forcing the nucleus to split
