History of
Radiation
Protection
Timeline Cards

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Mendeleev introduces the
I
1
H
1.008
Hydrogen
periodic system o
Periodic Tabli
f
a
element:
$
2
He
4.003


Atomic
Number
SYMBOL
Atomic Weight *
Name

Alkali metals
Alkali earth metals
Transition metals
Post-transition meta
Metlloid
Lanthanides
Actinides
Nonmetals
Hologens

3
Li
Lithium
4
Be
Beryllium

s
5
B
Boron
6
C
Carbon
7 N
8
0
9
F
Fluorine
10
Ne
11
Na
22.990
12
Mg
24.305
13
Al
26.982
14
Si
28.085
15
P
30.974
16
S
32.06
17
CI
35.45
18
Ar
39.948
Argon




19
K
Potnwlum
20
Ca
Calcium
21
Sc
22
Ti
Titanium
23
V
24
Cr
Chromium
25
Mn
26
Fe
27
Co
58.933
Cobalt
28
Ni
58.693
Nickel
29
Cu
Copper
30
Zn
Zinc
31
Ga
32
Ge
33
As
74.922
Arsenic
34
Se
33
Br
Bromine
36
Kr
37
Rb
85.468
Rubidium
38
Sr
87.62
Strontium
39
Y
88.906
40
Zr
91.224
Zirconium
41
Nb
92.906
Niobium
42
Mo
95.95
Molybdenum
43
Tc
(98)
Technetium
44
Ru
101.07
45
Rh
102.906
Rhodium
46
Pd
106.42
Palladium
47
Ag
107.868
Silver
48
Cd
112.414
49
In
114.818
Indium
50
Sn
118.710
Tin
51
Sb
121.760
Antimony
52
Te
127.60
53
1
126.904
54
Xe
131.293
55
Cs
132.905
56
Ba
137.327
Barium
51 /
11.
72
Hf
178.49
Hafnium
73
Ta
180.948
Tantalum
74
W
Tungsten
75
Re
186.207
Rhenium
76
Os
Osmium
77
lr
192.217
78
Pt
195.084
Platinum
79
Au
196.967
Gold
80
Hg
200.592
Mercury
81
TI
Thallium
82
Pb
207.2
83
Bi
208.980
Bismuth
84
Po
(209)
Polonium
85
At
(210)
Astatine
86
Rn
(222)
Radon
87
Fr
(223)
88
Ra
(226)
Radium
89/
-"j.03
104
Rf
(267)
105
Db
(268)
Oubnium
106
sg
(271)
107
Bh
(270)
Bohrlnm
108
Hs
(269)
109
Mt
(278)
110
Ds
(281)
111
Rg
1282)
Roentgenlum
112
Cn
(285)
113
Nh
(286)
Nlnonlum
114
Fl
(289)
Flerovlum
115
Mc
(289)
Moscovium
116
Lv
(293)
117
Ts
(294)
TennesBlne
118
og
(294)
Oganesson
Lanthanide
Series
57
La
138.905
58
Ce
140.116
Cerium
59
Pr
140.908
Praseodymium
60
Nd
144.242
Ncodymium
61
Pm
(145)
62
Sm
150.36
Samarium
63
Eu
151.964
Europium
64
Gd
157.25
Gadolinium
65
Tb
158.925
Terbium
66
Dy
162.500
Dysprosium
67
Ho
68
Er
167.259
Erbium
69
Tm
168.934
70
Yb
173.045
Ytterbium
71
Lu
174.967
Lutotium
Actinide
Series
89
Ac
<227)
Actinium
90
Th
232.038
Thorium
91
Pa
231.036
Protactinium
92
U
238.029
Uranium
93
Np
(237)
Neptunium
94
Pu
(244)
Plutonium
95
Am
A <243>
96
Cm
(247)
Curium
97
Bk
(247)
98
Cf
(251)
Californium
99
Es
(252)
Einsteinium
100
Fm
(257)
101
Md
(258)
Mendelevlum
102
No
(259)
Nobellum
103
Lr
<26rf
*() indicates the mass number of the longest-lived isotope.
Based on NIST 2017 Periodic Table

-------
Roentgen discovers basic
properties of x-rays

-------
Bequerel announces discovery of
radioactivity

-------
Curie discovers polonium and
radium and coins the term
"radioactivity*
88
84
Ra
Po
(226)
(209)

-------
X-rays and radium are widely
used
88
Ra
(226)

-------
Scientists begin to understand
f ission and the decay of
radioactive substances
Neutrons
Neutron

-------
American organizations adopt
British protection rules

-------
The first nuclear reactors
and atomic weapons are
developed

-------
The British Roentgen Society
resolves to protect people from
overexposure to x-rays

-------
Organizations form to
address radiation
protection in the United
States and overseas

-------
The Federal Radiation
Council is established

-------
Congress creates the
Environmental Protection
Agency

-------