Download Uranium-238 Decay Series

Uranium-238 Decay Series
Uranium, a radioactive element, decays to the stable element lead-206 by emitting alpha particle or beta
particles. Use the periodic table to dentify the elements by the number of proton in the nucleus.
Remember the atomic mass is the sum of protons and neutrons. Complete the following chart by following
these rules
1. Alpha emission- expel a positive alpha particle (2p+2N): lose two protons and two neutrons. The
atomic number drops by two, but the mass drops by 4.
2. Beta emissions (β or an electron) - expel a negative beta particle caused by the conversion of a
neutron to a proton +β particle: gain one proton, lose one neutron, overall mass stays the same.
3. Half-life abbreviations
s=seconds
m=minutes
d=days
y=years
Element
Uranium
Atomic
Mass
238
234
Type of Radiation
Radiation Emitted
Alpha particle
Beta particle
#Protons
#Neutrons
Half-Life
92
-2
90
146
-2
144
4.5 x 109y
1.17m
Beta particle
2.5 X 105y
Alpha particle
8.0 X 104y
Alpha particle
Radon (gas)
222
Seeps into air from the ground
1,620y
Alpha particle
3.82d
Alpha particle
3.05m
Alpha particle
26.8m
Beta particle
19.7m
Beta particle
1.6 x 10-4s
Alpha particle
19.4y
Beta particle
5.0d
Beta particle
Lead
206
Alpha particle
Stable Atom
24.1d
138d
82
124
Stable
Note: Lead 206 is stable and not radioactive. You have reached the end of the line!