NUCLEAR CHEMISTRY

THE NUCLEUS Inside the nucleus there are:

ProtonsNeutrons

The nucleus is held together by the strong nucleus force.

THE NUCLEUS The nucleus is not always

stable! The number of protons and

neutrons can influence the stability of the nucleus. Usually a 1:1 ratio is stable. More than this is unstable

Certain isotopes of elements are said to be unstable, and as a result they break down radioactive. All elements with an atomic

number above 82 have at least one radioactive isotope.

RADIOACTIVITY There are three major types

of radioactivity:

Composed of 2 protons and 2 neutrons

A helium nucleus

Made of a single negative charge

Basically an electron

High energy photon No mass

Alpha particles lost: A nucleus loses 2 protons and 2 electrons This produces a loose alpha particle and an atom that

is “lighter” with an atomic number lower by two and an atomic mass lower by 4 amus.

TYPES OF RADIOACTIVITY

TYPES OF RADIOACTIVITY Beta particles lost:

A neutron is made up smaller particles In radioactive isotopes sometimes a neutron

will spontaneously break apart, releasing a beta particle (electron).

What remains is a proton

The neutron breaks apart into a proton and an electron.

The electron is released from the nucleus and the proton stays.

TYPES OF RADIOACTIVITY Gamma Rays:

The most penetrating and high energy type of radioactivity.

Large amounts of photon energy is released The nucleus is unchanged in numbers of protons and

neutrons, but becomes more stable.

STRENGTH OF RADIOACTIVITY

Alpha particles are the most heavy but least penetrating.

Gamma rays are pure energy, have no mass, but are the most penetrating.

1. Fission: This occurs when a radioactive nucleus splits to form two smaller, more stable nuclei

This can lead to dangerous chain reactions!

NUCLEAR REACTIONS

1. FISSION: NUCLEAR REACTORS AND BOMBS

1. FISSION: NUCLEAR REACTORS AND BOMBS

A common source of Uranium-235 is used as a fuel in nuclear reactions.

It undergoes a number of reactions to release a great deal of energy, which in a reactor is harvested and used for power.

1. FISSION: NUCLEAR REACTORS AND BOMBS

Another common source of fuel is Uranium-238

The end result of all of the reactions is a stable isotope of lead!

NUCLEAR REACTIONS 2. Fusion: This type of reaction involves

two small nuclei coming together to form a larger nuclei.

This is how the sun works

2. FUSION Nuclear fusion produces an

enormous amount of energy, more than fission.

However the reaction is very unstable and dangerous.

Can only be contained in stars like the sun.