school
Acemy

Atomic Structure and Electron Configuration

AP Chemistry· difficulty 4/5

Cr (Z = 24) is best described as

  • A

    [Ar] 4s1 3d5[Ar]\,4s^1\,3d^5 — half-filled d shell stabilization

    check_circle
  • B

    [Ar] 4s0 3d6[Ar]\,4s^0\,3d^6

  • C

    [Ar] 4s2 3d4[Ar]\,4s^2\,3d^4 — strict aufbau order

  • D

    [Ar] 3d6[Ar]\,3d^6 — collapse of 4s subshell

Explanation

Cr breaks aufbau: half-filled 3d⁵ (and full 4s¹) lowers energy via exchange stabilization. Same anomaly in Mo, Cu, Au.

Want 10 more like this — adaptive to your weak spots?

Practice 10 like thisarrow_forwardPredict my AP score

Related questions

auto_awesomeAll Toolsquestion_answerHomework Q&Amenu_bookAP & SAT PreptimelineLearn Mode