Transition Metals for IB & OCR Chemistry | 过渡金属：IB与OCR化学考点精讲

📚 Transition Metals for IB & OCR Chemistry | 过渡金属：IB与OCR化学考点精讲

Transition metals occupy the central block of the periodic table and exhibit a rich variety of chemical behaviour, from variable oxidation states and colourful complex ions to crucial catalytic roles. In both the IB and OCR chemistry syllabuses, transition metal chemistry is a high-yield topic that integrates fundamental concepts of bonding, structure, redox, and periodicity. This article provides a focused revision of the key points.

过渡金属占据周期表的中部区，展现丰富多彩的化学性质，包括可变的氧化态、多彩的配合离子以及关键的催化作用。在 IB 和 OCR 化学大纲中，过渡金属化学是一个高权重主题，综合了化学键、结构、氧化还原和周期性等基础概念。本文提供考点精讲，帮助高效复习。

1. Defining Transition Metals | 过渡金属的定义

Transition metals are defined as d-block elements that form at least one stable ion with a partially filled d-subshell. This definition excludes scandium (Sc³⁺ is 3d⁰) and zinc (Zn²⁺ is 3d¹⁰) because their common ions have either empty or full d orbitals. Typical examples include iron, copper, chromium, and manganese.

过渡金属被定义为能形成至少一种具有部分填充d轨道的稳定离子的d区元素。该定义排除了钪（Sc³⁺为3d⁰）和锌（Zn²⁺为3d¹⁰），因为它们的常见离子具有全空或全满的d轨道。典型例子包括铁、铜、铬和锰。

The d-block encompasses the elements from Group 3 to Group 12, but not all are transition metals by this strict definition. The partially filled d-orbital requirement is responsible for many characteristic properties such as variable oxidation states, coloured compounds, and paramagnetism.

d区涵盖第3族到第12族元素，但根据严格定义并非全部都是过渡金属。部分填充d轨道的要求是许多特征性质的原因，如可变的氧化态、有色化合物和顺磁性。

2. Electronic Configurations & Oxidation States | 电子排布与氧化态

The electron configurations of transition metal atoms show a characteristic filling of the 3d subshell after the 4s orbital is occupied, obeying the (n+l) rule. For example, Fe is [Ar] 3d⁶ 4s², Cu is [Ar] 3d¹⁰ 4s¹. When forming ions, electrons are lost from the 4s orbital first, then from 3d. Hence Fe²⁺ is [Ar] 3d⁶, Fe³⁺ is [Ar] 3d⁵.

过渡金属原子的电子排布特点是先填充4s轨道再填充3d亚层，遵循 (n+l) 规则。例如，铁为 [Ar] 3d⁶ 4s²，铜为 [Ar] 3d¹⁰ 4s¹。形成离子时，电子先失去4s轨道上的，再失去3d上的。因此 Fe²⁺ 为 [Ar] 3d⁶，Fe³⁺ 为 [Ar] 3d⁵。

Variable oxidation states are a key property, such as Mn (+2, +4, +6, +7) and Cr (+2, +3, +6). The stability of higher oxidation states often involves strong covalent bonding with oxygen, as in Mn

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