Question

first 20 elements of the periodic table with atomic number and mass and weight​

Answer 1

Answer:

hydrogen 1 /mass2 helium 2 mass 4 lithium mass 6 no3 berillium mass 8 no 4 boron carbon mass 12 no 6 nitrogen mass 14 no 7 oxygen no 8 mass 16 fluorine no 9 mass 18 neon sodium magnesium aluminium silicon phosphorus sulphur chlorine argon potassium calcium mass is 40 no 20