Question

write first 20 elements (name, symbol, atomic number,mass number) repair periodic table
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Answer 1

Answer:

Explanation:

Element

Atomic number

Mass number

Hydrogen (H)

1

1

Helium(He)

2

4

Lithium(Li)

3

7

Beryllium(Be)

4

9

Boron(B)

5

11

Carbon(C)

6

12

Nitrogen(N)

7

14

Oxygen(O)

8

16

Fluorine(F)

9

19

Neon(Ne)

10

20

Sodium(Na)

11

23

Magnesium(Mg)

12

24

Aluminium(Al)

13

27

Silicon(Si)

14

28

Phosphorous(P)

15

31

Sulfur(S)

16

32

Chlorine(Cl)

17

35.5

Argon(Ar)

18

40

Potassium(K)

19

39

Calcium(Ca)

20

40