Periodic Table of Elements
Home › Elements › Element periods (1–7) › Period 3

Period 3

3 elements in this period. All elements in the same period occupy the same number of electron shells.

8 elements

11 Na Sodium 22.99 12 Mg Magnesium 24.305 13 Al Aluminum 26.982 14 Si Silicon 28.085 15 P Phosphorus 30.974 16 S Sulfur 32.07 17 Cl Chlorine 35.45 18 Ar Argon 39.9