Chemical bonds are the unions that exist between atoms or molecules with each other, to form a stable compound . An individual atom has some ability to combine with other atoms by losing or absorbing one, two, or more electrons from another atom. This ability to combine is called valence. An atom can have a positive valence, which means that it gives up electrons, while a negative valence indicates that it absorbs electrons. The same happens with some chemical compounds, which when dissociated acquire a positive or negative charge.
An atom or compound whose individual molecule is free and able to combine immediately is called an ion . Ions composed of only one atom are called monatomic. Compounds of several atoms or molecules are called polyatomic. There are positive ions with a positive charge, which are called cations, and those with a negative charge, called anions.
Types of chemical bonds
Atoms and chemical compounds are joined together by bonds . These bonds determine how compounds behave based on their nature and the interactions they have with their environment. There are three main types of chemical bonds.
Ionic bonds are those that occur mainly between non-metallic elements and some metalloids with each other . One of the elements is electropositive (cation) and one electronegative (anion); at room temperature they are usually solid, with a very high melting point. They are soluble in water, dissociating into their component ions. This happens, for example, when salt dissolves in water, leaving sodium cations (Na+) and Chlorine anions (Cl-) dissolved in the liquid. Passing an electric current through this solution conducts electricity (electrolysis).
Covalent bonds are those that occur mainly between atoms of the same element , where the bond is formed by pairs of electrons, and these are not broken and tend to electrically neutralize the molecule. At room temperature they are in liquid or gaseous state. These types of bonds are very common in carbon compounds, determining what type of hydrocarbon is being talked about. Carbon has valence +4 and -4. This means that it can give or receive four electrons. When the bond is monovalent, that is, a single pair of electrons joins two carbon atoms, we speak of alkanes. For example Pentane: C 5 H 12, in which the bonds between carbon atoms have a single covalent bond, that is, the bond is made with one electron from each carbon atom. When there is a double covalent bond in the same molecule of five carbon atoms, then it is of the type of hydrocarbons called alkenes, which are characterized by having a divalent bond. In this case, it will be called pentene and the formula will be C 5 H 10, since the pair of extra bonds that exist in one of the pairs of carbon atoms, will no longer connect with hydrogen atoms, so the number of hydrogens is reduced by two. When there is a trivalent bond, then the number of hydrogens will be reduced by two and in one of the carbon pairs there will be three covalent bonds, that is, a union in which three electrons of each carbon atom are linked. These hydrocarbons with trivalent bonds are called alkynes, and our compound will be called pentyne, with formula c 5 h 8 .
Covalent bonds can be broken
They occur when the electro activity of the compounds that bind is proportionally different, and for this reason the electrons remain close to the more electronegative nucleus for a longer time, which is why a positive and a negative pole can be defined for them.
It refers to the type of bonds where the electronegativity of the components are proportionally equal, that is, the electrons are relatively close to the two nuclei proportionally, leaving both ends (poles) with equal strength, understanding that there is no pole stronger.
They are those that present to each other the atoms of the metals. They are characterized in that the negatively charged electrons form a cloud around the nucleus, which has a positive charge. This cloud binds the metal atoms together, and due to this cloudy state, when an electric current passes, they easily create a flow of electrons, that is, they easily conduct electricity. They are insoluble in water.