为什么碳被认为是四价的?
碳与元素周期表中的氢、氧、铅和任何其他元素一样,是一种化学元素。碳是一种丰富的元素。钻石和石墨是纯碳或几乎纯碳的例子,尽管它们也可能与其他元素混合形成分子。人类、动物、植物、树木和土壤都有碳基分子作为它们的基本建筑成分。一些温室气体,如 CO 2和甲烷,以及主要由碳氢化合物组成的化石燃料,包括碳基化合物(由氢和碳组成的分子)。
二氧化碳是人类产生的最主要的温室气体,在气候变化的背景下通常被称为“碳”。但是,这在技术上并不正确。只有当每个碳原子结合两个氧原子时,它才会变成二氧化碳(因此二氧化碳的化学式为 CO 2 )。
Carbon is one of the most essential elements of the survival of life on Earth. Carbon consists of 0.025 % of the Earth. Although, this amount is less Carbon combines with many different elements and forms a huge number of compounds. Nearly all living and non-living things are made up of Carbon. Carbon has fifteen different isotopes ranging from C-8 to C-22.
碳原子序数为 6,原子构型为 2、4。碳位于元素周期表第 14 族的起始位置。第 14 族元素也称为碳族元素。
碳的性质
- 碳有多种形状和尺寸。煤和煤烟是最纯净的碳的两个例子。
- 颜色是光滑、单调的灰色或黑色。
- 木炭是最重要的碳化合物之一,它是在没有空气的情况下燃烧碳时产生的。
- 它可以以多种同素异形体形式存在。同素异形体是具有不同物理和化学特性的不同类型的元素。
- 不同种类的碳的密度因来源而异。有纯碳形式和非纯碳形式,例如煤,它是碳和氢的组合。
- 燃烧反应是碳化合物中发生的四种反应之一:氧化反应、加成反应和取代反应。
- 众所周知,碳需要氧气、热量和光来制造二氧化碳。燃烧是在空气中燃烧某物以产生二氧化碳的过程。
碳的化合价
碳原子的原子序数 6 (2,4) 有四个价电子,这意味着碳的结合能力为四,化合价为四。碳的四个不成对电子与其他四个原子结合形成键。碳和其他原子共享电子以形成键。为了获得完整的八位字节的稳定键形成是非常必要的。
碳可以形成+4阳离子的阳离子和-4价的阴离子。两者都是不稳定的。碳作为阳离子和阴离子的高度不稳定性质不支持碳中的Ionic键形成。
Why is Carbon considered as Tetravalent?
The main reason for calling Carbon tetravalent is because carbon has 4 valence electrons in its valence shell. This tetravalent nature of having 4 valence electrons in the outer shell of Carbon leads to carbon to share electrons and form covalent bonds to attain the nearest noble gas configuration of Neon. Four covalent bonds are formed by Carbon for attaining stability or nearest noble gas configuration. The covalent bond nature of Carbon is thus because of the tetravalent nature of Carbon.
The bond formation which therefore takes place in Carbon is Covalent in Nature.
Covalent bonding is the bond formation that takes place when there is no give or takes of electrons to form noble gas configuration and electrons are shared between two atoms to provide each other stability.
An example of Covalent Bond Formation observed in CO2 between atoms of Carbon and Oxygen is as below:
示例问题
问题1:定义同源序列。
回答:
A homologous series is a collection of compounds having comparable chemical characteristics and the same functional group, with the first member varying by −CH2 from the next. The same general formula may be used to describe members of a homologous series.
问题 2:导致我们周围出现大量碳化合物的碳的两个特性是什么?
回答:
Carbon has two qualities that lead to a large variety of compounds.
- Catenation: Catenation is the tendency of carbon atoms to bond together through covalent bonds to form chains and rings.
- Tetravalency: Carbon has a valency of four, which means it may bind with four additional carbon atoms or atoms of another element.
问题3:碳的原子序数是多少?
回答:
The atomic number of Carbon is 6
问题 4:给出碳原子的壳层构型。
回答:
The shell configuration of Carbon with atomic number 6 is 1s² 2s² 2p².
问题5:碳原子有多少个共价键?
回答:
The carbon atom can share its four available electrons to form four covalent bonds.