Edexcel A-Level Chemistry: Electron Configurations up to Z=36 | 爱德思A-Level化学：原子序数36以内的电子构型

📚 Edexcel A-Level Chemistry: Electron Configurations up to Z=36 | 爱德思A-Level化学：原子序数36以内的电子构型

Electron configuration is one of the most important tools in A-Level Chemistry because it links atomic structure to periodicity, bonding, ionisation energies and transition metal chemistry. This article focuses on the Edexcel specification point requiring you to deduce electronic configurations of atoms and ions up to Z = 36 using s, p and d orbitals.

电子构型是A-Level化学中最重要的工具之一，因为它将原子结构、元素周期律、化学键、电离能和过渡金属化学联系起来。本文聚焦爱德思考纲中要求掌握的内容：运用s、p、d轨道推断原子序数36以内原子和离子的电子构型。

1. Why Electron Configurations Matter | 为什么电子构型重要

Electron configurations describe the arrangement of electrons in atoms. For Edexcel A-Level Chemistry, specification point 1.19 requires you to deduce electron configurations of atoms and ions up to Z = 36 in terms of s, p and d orbitals. This skill supports periodicity, ionisation energy, bonding, redox and transition metal chemistry.

电子构型描述原子中电子的排列方式。爱德思A-Level化学考纲1.19要求你运用s、p、d轨道推断原子序数36以内原子和离子的电子构型。这项技能是周期律、电离能、化学键、氧化还原和过渡金属化学的重要基础。

2. Quantum Shells and Sub-shells | 量子壳层与子壳层

At A-Level, electrons occupy quantum shells labelled n = 1, 2, 3, 4. Each shell is divided into sub-shells: an s sub-shell holds 2 electrons, a p sub-shell holds 6, and a d sub-shell holds 10. Shell 1 has only 1s; shell 2 has 2s and 2p; shell 3 has 3s, 3p and 3d; shell 4 has 4s, 4p and 4d.

在A-Level中，电子占据主量子数n = 1、2、3、4的量子壳层。每个壳层分为子壳层：s子壳层最多容纳2个电子，p子壳层最多容纳6个，d子壳层最多容纳10个。第1层只有1s；第2层有2s和2p；第3层有3s、3p和3d；第4层有4s、4p和4d。

3. Orbital Filling Rules | 轨道填充规则

Always use three rules when filling orbitals. The Aufbau principle states that electrons enter the lowest-energy orbitals first. The Pauli exclusion principle states that one orbital can hold at most two electrons with opposite spins. Hund’s rule states that electrons occupy degenerate orbitals singly before pairing up.

填充轨道时始终遵循三条规则。构造原理（Aufbau principle）指出电子优先进入能量最低的轨道。泡利不相容原理指出一个轨道最多容纳两个自旋相反的电子。洪特规则要求电子在简并轨道中先单独占据，再配对。

4. Aufbau Order and Energy Sequence | 构造原理与能量顺序

For neutral atoms up to Z = 36, the sub-shell filling order is shown below. Notice that 4s fills before 3d, even though 3d is written before 4s in many completed configurations.

对于原子序数36以内的中性原子，子壳层填充顺序如下。注意4s先于3d填充，但在许多完整电子构型中3d写在4s之前。

1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p

The key point is that 4s is occupied before 3d during filling, but once electrons are present in 3d, the completed configuration is usually written with 3d before 4s. This convention makes ion formation easier to explain.

关键点是填充时4s先于3d被占据，但一旦3d中有电子，完整电子构型通常将3d写在4s之前。这种写法也便于解释离子形成。

5. Electron Configurations for Z = 1 to 18 | 1–18号元素的电子构型

For the first 18 elements, electrons fill only s and p sub-shells. The table below gives the full ground-state electronic configurations.

前18号元素只填充s和p子壳层。下表给出基态原子的完整电子构型。