Electron Configuration of Zirconium (Zr)
Zirconium (Zr, Z = 40) has the electron configuration [Kr] 4d^2 5s^2, filling 5 shells with 2, 8, 18, 10, 2 electrons.
This is the fast lane: one page, one fact, zero digressions. Read the quick answer, check the table, and if your exam needs the full derivation, the sections below walk through it step by step — in Bangla and English, like every page here. Need the whole picture instead — history, characteristics, uses, exam questions? The full Zirconium page is one click away.
Zirconium: every subshell, one by one
The table below unpacks [Kr] 4d^2 5s^2 line by line, so you can watch Zirconium's 40 electrons take their seats in order of increasing energy.
| Subshell | Electrons | Total so far |
|---|---|---|
| [Kr] | 0 | 36 |
| 4d | 2 | 38 |
| 5s | 2 | 40 |
Electrons per shell (K, L, M…)
Grouped by principal quantum number instead of subshell, Zirconium carries 2 in shell 1, 8 in shell 2, 18 in shell 3, 10 in shell 4, 2 in shell 5. The outermost shell holds 2 electrons — the ones that do all the bonding.
How to derive it yourself
Follow the aufbau order (1s → 2s → 2p → 3s → 3p → 4s → 3d → …), pouring 40 electrons into orbitals of capacity 2 (s), 6 (p), 10 (d) and 14 (f) until none remain. Write the filled inner shells as the nearest noble-gas core — for Zirconium that gives [Kr] 4d^2 5s^2.
Students also ask
How many electron shells does Zirconium have?
Zirconium is in period 5, so its electrons occupy 5 shells, holding 2, 8, 18, 10, 2 electrons respectively.
How many valence electrons does Zirconium have?
Its outermost shell holds 2 electrons, so Zirconium has 2 valence electrons that take part in bonding.
What is the noble-gas shorthand for Zirconium?
The shorthand form is exactly [Kr] 4d^2 5s^2.