Question

atomic number and velocity of first 20 elements​

Answer 1

Explanation:

Atomic no. Element Valency

1. Hydrogen 1

2. Helium 0

3. Lithium 1

4. Beryllium 2

5. Boron 3

6. Carbon 4

7. Nitrogen 3

8. Oxygen 2

9. Fluorine 1

10. Neon 0

11. Sodium 1

12. Magnesium 2

13. Aluminium 3

14. Silicon 4

15. Phosphorus 3,5

16. Sulphur 2

17. Chlorine 1

18. Argon 0

19. Potassium 1

20. Calcium 2

Hope it helps you.