what are the first 20 elements in the periodic table in order along with thier atomic and mass number?
Following is the list of first 20 elements with their names, symbols, atomic numbers and mass numbers
Element | Symbol | 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 |
Phosphorus | P | 15 | 31 |
Sulphur | S | 16 | 32 |
Chlorine | Cl | 17 | 35 |
Argon | Ar | 18 | 40 |
Potassium | K | 19 | 39 |
Calcium | Ca | 20 | 40 |