核言碎语（117）——原子的电离能

097 原子的电离能

Ionization Energy of Atoms

（https://www.nuclear-power.com/）

原子的电离能

Ionization energy, also called ionization potential, is the energy necessary to remove an electron from the neutral atom.

X + energy X+ + e

where X is any atom or molecule capable of being ionized, X+ is that atom or molecule with an electron removed (positive ion), and e is the removed electron.

电离能，又称电离势，是从中性原子中移去一个电子所必需的能量。

X+能量 X+ + e

其中X是任何能够被电离的原子或分子，X+是移除一个电子的原子或分子（正离子），e-是移除的电子。

There is an ionization energy for each successive electron removed. The electrons that circle the nucleus move in fairly well-defined orbits. Some of these electrons are more tightly bound in the atom than others. For example, only 7.38 eV is required to remove the outermost electron from a lead atom, while 88,000 eV is required to remove the innermost electron.

每一个连续的电子移除都有一个电离能。环绕原子核的电子在相当明确的轨道上运动。有些电子在原子中的束缚比其他电子更紧密。例如，从铅原子中移除最外层的电子只需要7.38 eV，而移除最内层的电子则需要88,000 eV。

• Ionization energy is lowest for the alkali metals which have a single electron outside a closed shell.
• 对于封闭壳层外只有一个电子的碱金属，电离能最低。
• Ionization energy increases across a row on the periodic maximum for the noble gases which have closed shells.
• 对于具有封闭壳层的惰性气体，电离能沿周期最大值一行递增。

For example, sodium requires only 496 kJ/mol or 5.14 eV/atom to ionize it. On the other hand neon, the noble gas, immediately preceding it in the periodic table, requires 2081 kJ/mol or 21.56 eV/atom.

例如，钠离子仅需496 kJ/mol或5.14 eV/原子即可电离。另一方面，元素周期表中紧挨着它的惰性气体氖，需要2081 kJ/mol或21.56 eV/原子。

The ionization energy associated with removal of the first electron is most commonly used. The nth ionization energy refers to the amount of energy required to remove an electron from the species with a charge of (n-1).

与移除第一个电子有关的电离能是最常用的。第n次电离能是指从带（n-1）电荷的物质中移去一个电子所需的能量。

1st ionization energy

第一电离能

X X+ + e

2nd ionization energy

第二电离能

X+ X2+ + e

3rd ionization energy

第三电离能

X2+ X3+ + e

For example, only 7.38 eV is required to remove the outermost electron from a lead atom, while 88,000 eV is required to remove the innermost electron.

例如，从铅原子中移除最外层的电子只需要7.38 eV，而移除最内层的电子则需要88,000 eV。

来源: wikipedia.org License: CC BY-SA 3.0

（待续）