Same chapter3 marksDifficulty: Medium
Write the electronic configuration of copper (Z = 29) and explain the anomaly.
Structure of Atom
3 marksDifficulty: Medium
Write the electronic configuration of chromium (Z = 24) and explain why it is not [Ar]3d44s2.
Original Khojo Papers practice question — not from a past board paper.
Answer
It is [Ar]3d54s1. A half-filled 3d subshell is unusually stable, because of the symmetry of the distribution and the exchange energy of five parallel electrons, so one 4s electron is promoted.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Copper, with [Ar]3d104s1, is stabilised in the same way by a completely filled subshell.
Related questions
From the same topic and chapter, at a similar level.
Same chapter3 marksDifficulty: Medium
How many electrons can the n = 3 shell hold, and how are they distributed among the subshells?
Structure of Atom
Same chapter3 marksDifficulty: Medium
State the de Broglie relation and Heisenberg's uncertainty principle.
Structure of Atom
Same chapter3 marksDifficulty: Medium
State the four quantum numbers and what each describes.
Structure of Atom
Same chapter3 marksDifficulty: Medium
State Hund's rule and the Aufbau principle.
Structure of Atom
Same chapter3 marksDifficulty: Medium
State the Pauli exclusion principle and one consequence of it.
Structure of Atom