nuclear chemistry bravo – 15,000 kilotons. ca standards
TRANSCRIPT
Nuclear Chemistry
Bravo – 15,000 kilotons
CA StandardsStudents know the three most common forms of radioactive decay (alpha, beta, and gamma) and know how the nucleus changes in each type of decay.
Students know alpha, beta, and gamma radiation produce different amounts and kinds of damage in matter and have different penetrations.
Students know some naturally occurring isotopes of elements are radioactive, as are isotopes formed in nuclear reactions.
Nuclear Symbols
Element symbol
Mass number (p+ + no)
Atomic number(number of p+)
U23592
Types of Radioactive Decay
alpha production ( , a He): helium nucleus
beta production ( , b e):
gamma ray production (g):
ThHeU 23490
42
23892
234 234 090 91 1Th Pa e
0023490
42
23892 2 ThHeU
NuclearStability
Decay will occur in such a way as to return a nucleus to the band (line) of stability.
Alpha Radiation
Alpha decay is limited to VERY large, nuclei such as those in heavy metals.
Beta Radiatio
n
Beta decay converts a neutron into a proton.
Alpha Particle Emission
Beta Particle Emission
Gamma Ray Emission
Symbol or or
Mass Heavy Light No Mass
How it changes the
nucleus
Decreases the mass number by 4
Decreases the atomic number by 2
Converts a neutron into a proton
Increases atomic number by 1
No change to the nucleus
Penetration Low Medium High
Protection provided by…
Skin Paper, clothing Lead
Danger Low Medium High
242He
242 e01 01 00
CA StandardsStudents know protons and neutrons in the nucleus are held together by nuclear forces that overcome the electromagnetic repulsion between the protons.
Students know the energy release per gram of material is much larger in nuclear fusion or fission reactions than in chemical reactions. The change in mass (calculated by E = mc2) is small but significant in nuclear reactions.
Fission
Fission - Splitting a heavy nucleus into two nuclei with smaller mass numbers.
Deuterium – Tritium Fusion Reaction
Fusion - Combining two light nuclei to form a heavier, more stable nucleus.
Energy and Mass
Nuclear changes occur with small but measurable losses of mass. The lost mass is called the mass defect, and is converted to energy according to Einstein’s equation:
DE = Dmc2
Dm = mass defect DE = change in energy
c = speed of light
Because c2 is so large, even small amounts of mass are converted to enormous amount of energy.
A Fission Reactor