Full configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁵ 5s²
In the short form, [Kr] stands for the 36 electrons of krypton, the noble gas before technetium. Only the electrons after it are written out.
Orbital diagram
4p↑↓↑↓↑↓
4d↑↑↑↑↑
5s↑↓
Outer subshells only. Each box is an orbital; electrons fill singly first (Hund's rule), then pair up with opposite spins.
What the configuration tells you
Technetium is in group 7, period 5, in the d-block. It has 5 unpaired electrons in the ground state, so the atom is paramagnetic.
Nearby elements
| Z | Element | Configuration |
|---|---|---|
| 40 | Zirconium | [Kr] 4d² 5s² |
| 41 | Niobium | [Kr] 4d⁴ 5s¹ |
| 42 | Molybdenum | [Kr] 4d⁵ 5s¹ |
| 44 | Ruthenium | [Kr] 4d⁷ 5s¹ |
| 45 | Rhodium | [Kr] 4d⁸ 5s¹ |
| 46 | Palladium | [Kr] 4d¹⁰ |
Questions students ask
What is the electronic configuration of technetium?
[Kr] 4d⁵ 5s², or in full, 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁵ 5s². Technetium has atomic number 43.
How many electrons are in each shell of technetium?
2, 8, 18, 13, 2 (K, L, M, N… shells in order).
How many unpaired electrons does technetium have?
5 in the ground state, so technetium atoms are paramagnetic.