252
11.
SPONTANEOUS DISINTEGRATION
‘
When expressed in percentage, the probable error is
67 Ve + Z
_
67
_
.
,» ..
W
_—
S \/Î"
(11—25)
where
_
_
a
——
b
S
\/5 + b
(11 26)
S is called
4 the relative sensitivity of the instrument.
11—12.
Radioactive Displacement Laws and Isotopes.——Radium, of atomic weight 226, emits an alpha particle of atomic
-
weight 4 and becomes radium emanation of atomic weight 222._
-
With the emission of an alpha particle, the nuclear charge and
its equivalent, the atomic number, decrease by two, changing
from 88 to 86.
That is to say, the chemical properties of radium
and its emanation are dilÏerent.
Radium, in turn, emits an alpha
particle and becomes radium A with atomic weight 218 (less by
4) and atomic number 84 (less by 2).
In general: For any alpha
ray transformation, the new element has an atomic weight [ess by four
units and an atomic number “less by two units than its parent.
Radium B emits a beta particle and becomes radium C. The
-
beta particles are electrons having a mass negligiblé in comparison
to thenuclear mass.
Hbnce, no essential difference exists between
the atomic weights (214) of radium B and C.
But the chemical
and physical properties of these two are different since the nuclear
charge has increased positively by an amount equal to one electron.
Thus, the atomic number of radium B is 82 while that of
radium C is 83.
In general:
For any beta ray transformation, the
ï
new element has the same atomic weight as its parent but an atomic
number greater by one. ’
Following these displaeement laws, the location of any radio'
active element inthe periodic table can be_determined. The
accompanying table of radioactive elements shows such an arrange—
_
ment_(gure 11—6).
_'
,
_
,
’
_
Those elements in the same vertical column have the same
'
atomic number although theif_“atomic weights di‘er, which means
’
that they have the same chemical and physical properties except
"
atomic weight. They are
thus grouped together at the same place
in
the periodic table. In other words, all. elements in a vertical
11.
SPONTANEOUS DISINTEGRATION
‘
When expressed in percentage, the probable error is
67 Ve + Z
_
67
_
.
,» ..
W
_—
S \/Î"
(11—25)
where
_
_
a
——
b
S
\/5 + b
(11 26)
S is called
4 the relative sensitivity of the instrument.
11—12.
Radioactive Displacement Laws and Isotopes.——Radium, of atomic weight 226, emits an alpha particle of atomic
-
weight 4 and becomes radium emanation of atomic weight 222._
-
With the emission of an alpha particle, the nuclear charge and
its equivalent, the atomic number, decrease by two, changing
from 88 to 86.
That is to say, the chemical properties of radium
and its emanation are dilÏerent.
Radium, in turn, emits an alpha
particle and becomes radium A with atomic weight 218 (less by
4) and atomic number 84 (less by 2).
In general: For any alpha
ray transformation, the new element has an atomic weight [ess by four
units and an atomic number “less by two units than its parent.
Radium B emits a beta particle and becomes radium C. The
-
beta particles are electrons having a mass negligiblé in comparison
to thenuclear mass.
Hbnce, no essential difference exists between
the atomic weights (214) of radium B and C.
But the chemical
and physical properties of these two are different since the nuclear
charge has increased positively by an amount equal to one electron.
Thus, the atomic number of radium B is 82 while that of
radium C is 83.
In general:
For any beta ray transformation, the
ï
new element has the same atomic weight as its parent but an atomic
number greater by one. ’
Following these displaeement laws, the location of any radio'
active element inthe periodic table can be_determined. The
accompanying table of radioactive elements shows such an arrange—
_
ment_(gure 11—6).
_'
,
_
,
’
_
Those elements in the same vertical column have the same
'
atomic number although theif_“atomic weights di‘er, which means
’
that they have the same chemical and physical properties except
"
atomic weight. They are
thus grouped together at the same place
in
the periodic table. In other words, all. elements in a vertical