Editing Openai/6946f4fa-e8bc-800b-b77e-c62f6390a97c (section)

=== （Molecular Orbital Theory） ===

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===== a. C₂ is paramagnetic. =====
b. C₂ is diamagnetic.
c. The carbon–carbon bond in C₂²⁻ is stronger than the one in CH₃CH₃.
d. The carbon–carbon bond in C₂²⁻ is shorter than the one in CH₃CH₃.
e. Two of the above.

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====== - 12 個價電子 ======
* MO 填法（B₂、C₂、N₂ 類型）
* 所有電子成對 👉 C₂ 是抗磁性（diamagnetic）

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* 錯 ❌ C₂ 沒有未成對電子

====== - 對 ✅ ======

====== - C₂²⁻：鍵階 = 3 ======
* CH₃CH₃：C–C 單鍵，鍵階 = 1 👉 鍵階越大 → 鍵越強 ✅ 正確

====== - 鍵階高 → 鍵短 ✅ 正確 ======

===== - ❌ a =====
* 其他皆正確

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===== a. For NO, the molecular orbital model is preferred over the localized electron model because NO contains an unpaired electron. =====
b. Electrons in antibonding orbitals will cause a molecule to be paramagnetic.
c. According to the molecular orbital model, when bonding occurs between hydrogen and bromine to make HBr, the 1s orbital of hydrogen no longer exists.
d. Antibonding electrons are higher in energy than the atomic orbitals from which they came.
e. At least two of the above are incorrect.

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* NO 有 1 個未成對電子
* Lewis 結構不好處理磁性
* MO 模型能正確預測順磁性 ✅ 正確

===== - ❌ 錯誤說法 =====
* 是否順磁取決於「有沒有未成對電子」
* 反鍵電子若成對 → 仍是抗磁性 ❌ 不正確

===== - 在 MO 理論中，原子軌域組合成分子軌域 =====
* 原本的原子軌域「不再是獨立存在」 ✅ 正確（MO 語言）

===== - 這正是「反鍵」的定義 ✅ 正確 =====

===== - 只有 b 是錯的 ❌ 錯誤 =====

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