This type of bonding occurs between two atoms of the same element or of elements close to each other in the periodic table. This bonding occurs primarily between nonmetals; however, it can also be observed between nonmetals and metals.
If atoms have similar electronegativities the same affinity for electrons , covalent bonds are most likely to occur. Because both atoms have the same affinity for electrons and neither has a tendency to donate them, they share electrons in order to achieve octet configuration and become more stable. In addition, the ionization energy of the atom is too large and the electron affinity of the atom is too small for ionic bonding to occur.
For example: carbon does not form ionic bonds because it has 4 valence electrons, half of an octet. To form ionic bonds, Carbon molecules must either gain or lose 4 electrons. This is highly unfavorable; therefore, carbon molecules share their 4 valence electrons through single, double, and triple bonds so that each atom can achieve noble gas configurations. Covalent bonds include interactions of the sigma and pi orbitals; therefore, covalent bonds lead to formation of single, double, triple, and quadruple bonds.
In this example, a phosphorous atom is sharing its three unpaired electrons with three chlorine atoms. In the end product, all four of these molecules have 8 valence electrons and satisfy the octet rule.
Ionic and covalent bonds are the two extremes of bonding. Polar covalent is the intermediate type of bonding between the two extremes. Some ionic bonds contain covalent characteristics and some covalent bonds are partially ionic.
For example, most carbon-based compounds are covalently bonded but can also be partially ionic. Polarity is a measure of the separation of charge in a compound. A compound's polarity is dependent on the symmetry of the compound and on differences in electronegativity between atoms.
Polarity occurs when the electron pushing elements, found on the left side of the periodic table, exchanges electrons with the electron pulling elements, on the right side of the table. This creates a spectrum of polarity, with ionic polar at one extreme, covalent nonpolar at another, and polar covalent in the middle. Both of these bonds are important in organic chemistry. Ionic bonds are important because they allow the synthesis of specific organic compounds.
Scientists can manipulate ionic properties and these interactions in order to form desired products. Covalent bonds are especially important since most carbon molecules interact primarily through covalent bonding. Polymer structures typically are long chains of covalently bonded carbon and hydrogen atoms in various arrangements.
Metallic bonding Definition: A metallic bond is formed when the valence electrons are not associated with a particular atom or ion, but exist as a "cloud" of electrons around the ion centers. Metallic materials have good electrical and thermal conductivity when compared to materials with covalent or ionic bonding.
A metal such as iron has metallic bonding. Example: In the real and imperfect world, most materials do not have pure metallic, pure covalent, or pure ionic bonding; they may have other types of bonding as well. For example, iron has predominantly metallic bonding, but some covalent bonding also occurs.
How can I count valence electrons? How can I calculate the valence electrons of transition metals? How can I calculate the valence electrons of ions? How many valence electrons does sodium have?
How many valence electrons are in an atom of phosphorus? How do you calculate the number of valence electrons in an atom? See all questions in Valence Electrons.
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