30 first chemical elements

hydrogen

H

1 amu

I

1 proton

helium

He

4 amu

2 protons

lithium

Li

7 amu

II

3 protons

beryllium

Be

9 amu

II

4 protons

boron

B

11 amu

III

5 protons

carbon

C

12 amu

III

6 protons

nitrogen

N

14 amu

II, III, IV, V

7 protons

oxygen

O

16 amu

II

8 protons

fluorine

F

19 amu

I

9 protons

neon

Ne

20 amu

10 protons

sodium

Na

23 amu

I

11 protons

magnesium

Mg

24 amu

II

12 protons

aluminium

Al

27 amu

III

13 protons

silicon

Si

28 amu

iV

14 protons

phosphorus

P

31 amu

III, V

15 protons

sulfur

S

32 amu

II, IV, VI

16 protons

chlorine

Cl

35,5 amu

I

17 protons

argon

Ar

40 amu

18 protons

potassium

K

39 amu

I

19 protons

calcium

Ca

40 amu

II

20 protons

chrominium

Cr

52 amu

II, III

24 protons

manganese

Mn

55 amu

II, IV, VII

25 protons

iron

Fe

56 amu

II, III

26 protons

nickel

Ni

59 amu

II

28 protons

copper

Cu

64 amu

I, II

29 protons

bromine

Br

80 amu

I

35 protons

krypton

Kr

84 amu

36 protons

silver

Ag

108 amu

I

47 protons

iodine

I

127 amu

I, II, III

53 protons

barium

Ba

137 amu

II

56 protons

gold

Au

197 amu

I, III

79 protons

mercury

Hg

201 amu

I, II

80 protons

lead

Pb

207 amu

II, IV

82 protons