Each main energy level (shell) around the nucleus has a maximum number of electrons it can hold, given by the formula 2n22n^22n2, where nnn is the shell number (1, 2, 3, 4 …).

Here’s how many electrons each level can hold:

  • 1st level (n = 1): 2 electrons max.
  • 2nd level (n = 2): 8 electrons max.
  • 3rd level (n = 3): 18 electrons max.
  • 4th level (n = 4): 32 electrons max.

For a simple school‑level model, you’ll often see it summarized for common elements as:

  • Level 1: 2
  • Level 2: 8
  • Level 3: 8 or 18 (basic diagrams usually show 8, more advanced ones allow up to 18)
  • Level 4: up to 32

Quick Scoop

  • The pattern comes from 2n22n^22n2:
    • 2(12)=22(1^2)=22(12)=2
    • 2(22)=82(2^2)=82(22)=8
    • 2(32)=182(3^2)=182(32)=18
    • 2(42)=322(4^2)=322(42)=32.
  • In real atoms, not every level fills to its maximum; electrons may start filling a higher level before a lower one is completely full because of detailed orbital energies (like 4s filling before 3d).

If you just need a fast answer for basic chemistry: think “2, 8, 18, 32 …” for the maximum electrons in levels 1, 2, 3, 4 and beyond.

Information gathered from public forums or data available on the internet and portrayed here.