Name

Atomic Weight

Abundance

Name

Atomic Weight

Abundance

1

H

hydrogen

1.01

12.00

57

La

lanthanum

138.91

1.20

2

He

helium

4.00

10.99

58

Ce

cerium

140.12

1.61

3

Li

lithium

6.94

1.16

59

Pr

praseodymium

140.91

0.78

4

Be

beryllium

9.01

1.15

60

Nd

neodymium

144.24

1.47

5

B

boron

10.81

2.6

61

Pm

promethium

(145)

6

C

carbon

12.01

8.55

62

Sm

samarium

150.36

0.97

7

N

nitrogen

14.01

7.97

63

Eu

europium

151.97

0.54

8

O

oxygen

16.00

8.87

64

Gd

gadolinium

157.25

1.07

9

F

fluorine

19.00

4.56

65

Tb

terbium

158.93

0.33

10

Ne

neon

20.18

8.08

66

Dy

dysprosium

162.50

1.15

11

Na

sodium

22.99

6.31

67

Ho

holmium

164.93

0.50

12

Mg

magnesium

24.31

7.58

68

Er

erbium

167.26

0.95

13

Al

aluminum

26.98

6.48

69

Tm

thulium

168.93

0.13

14

Si

silicon

28.09

7.55

70

Yb

ytterbium

173.04

0.95

15

P

phosphorus

30.97

5.57

71

Lu

lutetium

174.97

0.12

16

S

sulfur

32.07

7.27

72

Hf

hafnium

178.49

0.73

17

Cl

chlorine

35.45

5.27

73

Ta

tantalum

180.95

0.13

18

Ar

argon

39.94

—

74

W

tungsten

183.85

0.68

19

K

potassium

39.10

5.13

75

Re

rhenium

186.21

0.27

20

Ca

calcium

40.08

6.34

76

Os

osmium

190.2

1.38

21

Sc

scandium

44.96

3.09

77

Ir

iridium

192.22

1.37

22

Ti

titanium

47.88

4.93

78

Pt

platinum

195.08

1.68

23

V

vanadium

50.94

4.02

79

Au

gold

196.97

0.83

24

Cr

chromium

52.00

5.68

80

Hg

mercury

200.59

1.09

25

Mn

manganese

54.94

5.53

81

Tl

thallium

204.38

0.82

26

Fe

iron

55.85

7.51

82

Pb

lead

207.2

2.05

27

Co

cobalt

58.93

4.91

83

Bi

bismuth

208.98

0.71

28

Ni

nickel

58.69

6.25

84

Po

polonium

(209)

29

Cu

copper

63.55

4.27

85

At

astatine

(210)

30

Zn

zinc

65.39

4.65

86

Rn

radon

(222)

31

Ga

gallium

69.72

3.13

87

Fr

fancium

(223)

32

Ge

germanium

72.61

3.63

88

Ra

radium

(226)

33

As

arsenic

74.92

2.37

89

Ac

actinium

(227)

34

Se

selenium

78.96

3.35

90

Th

thorium

232.04

35

Br

bromine

79.90

2.63

91

Pa

protractinium

231.04

0.08

36

Kr

krypton

83.80

3.23

92

U

uranium

238.03

37

Rb

rubidium

85.47

2.40

93

Np

neptunium

(237)

-0.47

38

Sr

strontium

87.62

2.93

94

Pu

plutonium

(244)

39

Y

yttrium

88.91

2.22

95

Am

americium

(243)

40

Zr

zirconium

91.22

2.61

96

Cm

curium

(247)

41

Nb

niobium

92.91

1.40

97

Bk

berkelium

(247)

42

Mo

molybdenum

95.94

1.96

98

Cf

californium

(251)

43

Tc

technetium

   (98)

99

Es

einsteinium

(252)

44

Ru

ruthenium

101.07

1.82

100

Fm

fermium

(257)