Question
Complete the following table.
| Elements | Atomic number | Mass number | Protons | Electrons | neutrons | Electronic configuration | Valency |
| Chlorine | $17$ | ___ | ___ | ___ | $18$ | ___ | ___ |
| Silicon | ___ | $28$ | ___ | $14$ | ___ | ___ | ___ |
| Fluorine | ___ | ___ | $9$ | ___ | $10$ | ___ | ___ |
