Transcript Nuclear Chemistry - gcisd

Nuclear Chemistry
Ch. 21
Radioactive Emissions
Alpha decay – He nucleus
4
2
He
What product is formed when radium-226 undergoes alpha
decay?
What element undergoes alpha decay to form lead-208?
Beta particles – created by the conversion of a
neutron in the nucleus to a proton and an
electron (beta particle); the proton remains in
the nucleus while the beta particle is ejected
0
1
e
Iodine-131 undergoes decay by beta emission
Lead-209 undergoes decay by beta emission
Electron Capture

An inner shell electron is pulled into the
nucleus where it combines with a proton to
form a neutron; so atomic number
decreases by 1, but atomic mass stays the
same

Mercury-201 undergoes electron capture
Gamma Rays – does not result in a
change in the property of the atom
0
0

Atomic number (Z) = number of protons in nucleus
Mass number (A) = number of protons + number of neutrons
= atomic number (Z) + number of neutrons
Mass Number
Atomic Number
A
ZX
Element Symbol
proton
1p
1H
or
1
1
neutron
1n
0
electron
0b
0e
or
-1
-1
positron
0b
0e
or
+1
+1
a particle
4He
4a
or
2
2
A
1
1
0
0
4
Z
1
0
-1
+1
2
23.1
Learning Check
What radioactive isotope is produced in
the following bombardment of boron?
10B
5
+ 4He
2
? +
1n
0
Learning Check
What radioactive isotope is produced in
the following bombardment of boron?
10B
5
+ 4He
2
13N
7
+
1n
0
Half-Life

Time required for half of any given quantity
of a substance to react