• 16 parts
  • Checked October 2026

Aufbau Diagram Worksheet

A blank energy ladder from 1s to 5p to fill with arrows, with oxygen worked at the foot.

Aufbau Diagram Worksheet

Name Date

Blank sheet

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
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Write the name of each numbered part.Answer key

  1. 1s
  2. 2s
  3. 2p
  4. 3s
  5. 3p
  6. 4s
  7. 3d
  8. 4p
  9. 5s
  10. 4d
  11. 5p
  12. Orbital
  13. Electron pair
  14. Unpaired electron
  15. Subshell (sublevel)
  16. Shell (energy level)

Drawn for this site on 2026-10-03 by a script from this page's own table of sublevels. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Next: electron configuration questions

All 16 parts on the diagram

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The energy ladder 11

  1. 1s One orbital that holds 2 electrons. It fills first.
  2. 2s One orbital that holds 2 electrons. It fills after 1s and before 2p.
  3. 2p Three orbitals that hold 6 electrons in all. It fills after 2s and before 3s.
  4. 3s One orbital that holds 2 electrons. It fills after 2p and before 3p.
  5. 3p Three orbitals that hold 6 electrons in all. It fills after 3s and before 4s.
  6. 4s One orbital that holds 2 electrons. It fills after 3p and before 3d.
  7. 3d Five orbitals that hold 10 electrons in all. It fills after 4s and before 4p.
  8. 4p Three orbitals that hold 6 electrons in all. It fills after 3d and before 5s.
  9. 5s One orbital that holds 2 electrons. It fills after 4p and before 4d.
  10. 4d Five orbitals that hold 10 electrons in all. It fills after 5s and before 5p.
  11. 5p Three orbitals that hold 6 electrons in all. It fills after 4d, last on this sheet.

One filled diagram 5

  1. Orbital One box. It holds two electrons at most.
  2. Electron pair Two electrons in one orbital, with opposite spins.
  3. Unpaired electron One electron alone in its orbital.
  4. Subshell (sublevel) The orbitals of one row: here the three 2p orbitals.
  5. Shell (energy level) Every orbital with the same number: here 2s and 2p.

How this list was compiled: Every name and number checked on 2026-10-03 and kept only where two of these texts give it. (1) Purdue University, general chemistry topic review, Quantum Numbers and Electron Configurations: shells and subshells; one orbital in an s subshell, three in a p and five in a d, filled by 2, 6 and 10 electrons; the order of increasing energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, read off a table with arrows drawn at 45 degrees; the aufbau principle; Hund's rules; an arrow pointing up or down for each electron; oxygen as 1s2 2s2 2p4, its eighth electron filling one 2p orbital with the opposite spin; chromium and copper as exceptions. (2) Wikipedia, text only, Aufbau principle, Electron pair and Unpaired electron: the same filling order, also called the diagonal rule; 2, 6 and 10 electrons at most in s, p and d subshells; Hund's rule and the Pauli exclusion principle; an electron pair as two electrons in one orbital with opposite spins; an unpaired electron as one that occupies an orbital singly. (3) Jim Clark, Chemguide, Atomic Orbitals and Electronic Structures of Atoms: orbitals drawn as boxes with the electrons as arrows, one up and one down; energy levels; the order 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, with 5s before 4d; orbitals filled singly before pairing; oxygen with one paired and two single 2p electrons. (4) Chemistry LibreTexts, supplemental module Hund's Rules (a university wiki text): each orbital of a sublevel takes one electron before any takes two; unpaired electrons. Licence: own work

The drawing: Drawn for this site on 2026-10-03 by a script from this page's own table of sublevels; plain geometry, nothing traced or copied. Licence: own work

How it works

This aufbau diagram worksheet is a blank orbital diagram worksheet to print: rows of empty boxes from 1s to 5p, rising in the order they fill, enough for any element up to xenon. Oxygen is filled in at the foot.

Read the full guide

Filling in the blank diagram

Count the element's electrons and draw one arrow for each. Start at the lowest row and work up, following the arrows of the diagonal rule: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p.

Three rules for the arrows

Lower rows fill first: the aufbau principle. A box holds two arrows at most, one up and one down: the Pauli exclusion principle. In a row of several boxes every box gets one arrow before any gets a second: Hund's rule.

  • Chromium and copper are two of the elements whose real arrangement differs from the one the ladder predicts.

Questions and answers

What is an aufbau diagram?

A chart of an atom's sublevels drawn as rows of boxes in order of energy, lowest at the bottom. Electrons go in as arrows from the bottom up. Aufbau is German for building up.

What is the order of filling in an aufbau diagram?

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, and then 6s. The 4s row fills before 3d, and 5s before 4d.

How many electrons fit in each sublevel?

An s sublevel has one orbital and holds 2 electrons. A p sublevel has three orbitals and holds 6. A d sublevel has five orbitals and holds 10.

What is Hund's rule?

In a sublevel with several orbitals, each orbital gets one electron before any gets a second, and the single electrons share the same spin. Oxygen's 2p row shows it: one pair and two single arrows.

Why does 4s fill before 3d?

In the filling order the 4s sublevel comes just below 3d in energy. The n + l rule gives the same answer: 4 + 0 is less than 3 + 2.

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