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the valence of [element]
The valence of carbon is four.
碳的化合价是四。
化合价；原子价
valences — plural of valence
先理解核心含义，再看它在真实句子里的用法。
化合价；原子价
chemistry: the combining power of an atom or radical, expressed by the number of hydrogen atoms (or equivalent) it can combine with
The valence of carbon is four.
碳的化合价是四。
化学用语
原子、官能团或基团的化合能力,由它能结合的氢原子数或与其他原子结合时获得、失去或共享的电子数决定。
The combining capacity of an atom, functional group, or radical determined by the number of atoms of hydrogen with which it will unite, or the number of electrons that it will gain, lose, or share when it combines with other atoms, etc.
分子(如抗体或抗原)的结合位点数目。
The number of binding sites of a molecule, such as an antibody or antigen.
动词能够具有的论元数量,包括主语,范围从零到三,或较少见的四。
The number of arguments that a verb can have, including its subject, ranging from zero to three or, less commonly, four.
某人赋予某物的价值。
The value which a person places on something.
Carbon has a valence of four, so it can form many different compounds.
碳的化合价为四，因此它能形成许多不同的化合物。
In this molecule, the valence of each atom determines how many bonds it can make.
在这个分子中，每个原子的化合价决定了它能形成多少个化学键。
Students in chemistry class learned that oxygen usually has a valence of two.
化学课上的学生学到，氧通常的化合价是二。
The valence of carbon is four.
碳的化合价是四。
该词在化学中指“化合价”，在生物学中则指与抗原等结合的结合效价。
Oxygen has a valence of two.
氧具有二价。
Not this
Oxygen has valence of two.
Use this
Oxygen has a valence of two.
汉语说“氧的化合价为2”，没有冠词概念，但英语中 valence 在此是可数名词单数，前面需要冠词 a，所以应说 a valence of two。
Not this
Oxygen is valence two.
Use this
Oxygen has a valence of two.
汉语“氧是二价”不能直译为 Oxygen is valence two，因为 valence 是名词而非形容词。英语表达“化合价是多少”用 have a valence of 加数字，或用形容词 divalent。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
价电子
The number of valence electrons determines how an atom reacts.
价电子的数量决定了原子如何反应。
价电子壳层
Elements in the same group have the same number of electrons in their valence shell.
同一族的元素具有相同数量的价电子壳层电子。
价键
The valence bond theory explains how atoms form molecules by overlapping atomic orbitals.
价键理论通过原子轨道重叠解释原子如何形成分子。
价带
Electrons in the valence band are tightly bound to the atom.
价带中的电子与原子结合得很紧密。
价态
Iron can have valence states of +2 or +3 in its compounds.
铁在其化合物中可呈现+2或+3的价态。
Use valences naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
val- 开头像 value（数值），记住原子的“价值”就是它的化合价，决定能结合几个原子。
语域：formal 常见场景：chemistry textbooks and journals、biology/immunology literature 该词为专业术语，通常用于化学或生物学的学术语境，多出现在教材、论文等书面材料中；日常口语中较少使用。
真正与 valence (/ˈveɪləns/) 押韵的是 surveillance (/sərˈveɪləns/)，两者重读音节后的 /veɪləns/ 相同。拼写相近的 -lence 词如 silence (/ˈsaɪləns/)、violence (/ˈvaɪələns/)、excellence (/ˈɛksələns/)、prevalence (/ˈprɛvələns/) 重读元音不同，不押韵；evidence (/ˈɛvɪdəns/) 以 -ence 结尾但读音为 /əns/。
Dictionary facts from ECDICT, WIKTIONARY.