价层 meaning in English

valence shells

In this model the arrangement of bonds around the central atom is considered to depend upon how many valence-shell electron pairs .
在这个模型中，认为围绕中心原子的化学键的排列取决于价层中电子对的数量。
On the influence of orbital energy of halogenous atom s on certain properties of halogens
卤原子的价层轨道能量对卤素某些性质的影响
The ability of carbon to form stable compounds in such astonnishing numbers arises in that it utilizes its four valence electrons completely in the establishment of four covalence , its valence shell becomes saturzted
试译一下：碳能组成（有着）如此惊人数量的稳定的化合物在于它在四价共价健的建立中充分利用自己的四价电子，它的化学价层才能得以饱和。