Nuclear Chemistry
What’s going on here?
Sub-Atomic Particles
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What are atoms made of?
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
name symbol
Electron
eProton
p+
Neutron
no

What are protons & neutrons made of?

Quarks! up, down, strange, charm…


location
mass
charge
orbitals
negligible*
nucleus 1 atomic mass unit +
nucleus
1* amu
0
Elements & Isotopes

For every element, the atomic number is the number of
protons (and electrons in an electrically neutral atom).

The mass number is the total number of nucleons
(protons & neutrons) in the nucleus.

Atoms (of the same element) that have different numbers
of neutrons are called isotopes.

Isotopes are named by there mass number. (carbon-14)
Radioactivity – a hot topic!

Isotopes with too many (or too few) neutrons are
unstable. (The further from the atomic weight, the
more unstable.)

To become stable, they give off radiation in process
called radioactive decay.

Radioactive decay changes the mass number and/or the
atomic number until the atom reaches a more stable isotope.

Radioactive decay also releases energy in the form of
radiation. (alpha, beta & gamma…)
Nuclear Radiation – It’s hot!

Name symbol
composition
penetration/damage

Alpha
a
2p+ & 2no
low / high

Beta
b
e-
medium

Gamma
g
EMR (high f light)
high / low

Positron* e+
anti matter!!!
medium
Nuclear Reactions – You’re hot!

Decay – spontaneous breakdown of unstable nuclii





Fission – splitting heavy nuclii


Step by step trip to stability  most stable isotope
Extra protons  beta decay (increases atomic number)
Extra neutrons  alpha decay (decreases Mass# & atomic #)
Characterised by a unique rate of decay  half-life
Nuclear reactors & atomic bombs, dangerous waste
Fusion – joining light nuclii

Stars & H (hydrogen) bombs, requires ultra-high P & T