Question

mass number of first 20 elements

Answer 1

Hydrogen

 

1    H 1

Helium

 

4   He 2

Lithium

 

7   Li 3

Beryllium

 

9    Be 4

Boron

 

11     B  5

Carbon

 

12    C 6

Nitrogen

 

14     N 7

Oxygen

 

16   O 8

Fluorine

 

19   F 9

Neon

 

20 Ne 10

Sodium

 

23 Na 11

Magnesium

 

24   Mg 12

Aluminium

 

27  Al 13

Silicon

 

28  Si 14

Phosphorus

 

31   P 15

Sulphur

 

32   S 16

Chlorine

 

35.5  Cl

Argon

 

40   Ar 18

Potassium

 

39 K 19

Calcium

 

40 Ca 20



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Answer 2

Answer:

mass number of first 20 elements expressed by chemical symbol.

Explanation:

H-1

He-4

Li-6

Be-9

B-10

C-12

N-14

O-15

F-18

Ne-20

Na-22

Mg-24

Al-26

Si-28

P-30

S-32

Cl-35.5

Ar-39

K-39

Ca-40

God bless you all

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