Ch 4. Nuclear Chemistry Flashcards
What is nuclear fusion?
A reaction in which the nucleus of one element fuses with the nucleus of a different element, creating the nucleus of a heavier element.
Under what conditions can nuclear fusion occur?
High heat and pressure.
Give an example of a nuclear fusion reaction.
Hydrogen (Mass no. 1) + Hydrogen (Mass no. 2) = Helium (Mass no. 3)
What is released in a nuclear fusion reaction?
Huge amounts of energy, in the form of;
light,
heat,
and cosmic rays
What are cosmic rays (or cosmic radiation)?
A form of radiation which comes from the Sun.
What is an isotope?
Atoms with the same atomic number, but different mass numbers (number of neutrons).
Why does nuclear fusion occur?
Some isotopes are naturally unstable.
Changes in the nucleus allow the atom to become more stable.
What effect does nuclear fusion have?
The changes to the nucleus produce energy and small particles which fire out from the nucleus. The energy and particles are known as radiation and the unstable atoms are described as radioisotopes.
How does nuclear fusion occur?
- Unstable isotopes disintegrate (decay) spontaneously.
- As they decay, they emit particles of radiation and release energy.
- The isotopes become more stable in the process.
What does the stability of an atom depend on?
The ratio of protons to neutrons in its nucleus.
What is background radiation?
Radiation we receive everyday. It can come from many artificial and natural sources.
How can radioisotopes become more stable?
By emitting radioactive particles or re-arranging themselves whilst releasing energy.
What are the 3 common types of radiation particles?
- Alpha
- Beta
- Gamma
How many protons and neutrons are found in the nucleus of an alpha particle?
2 protons. 2 neutrons.
What is the mass of an alpha particle?
4 amu
What is the charge of an alpha particle?
positive (+2)
How can alpha particles be stopped?
Due to their size they are relatively heavy and slow moving. They do not travel very far in the air and can be stopped by a few cm of air of a sheet of paper.
How are Beta particles formed?
Beta particles consist of a high energy/speed electron which is formed when a neutron splits into a proton and an electron.
What is the mass of a Beta particle?
0 amu
What is the charge of a Beta particle?
negative (-1)
What material must be used to stop Beta particles?
Since Beta can penetrate much further than alpha particles, the require a thin sheet of aluminium to stop them.