Lewis, Kossel and Longmuir tried to explain why atoms combine according to the electronic configuration of noble gases. They hypothesized that noble gas atoms did not tend to form bonds with other atoms due to their stable configuration of eight electrons, which they called bytes. This tendency of atoms to complete their byte is called the byte rule. Noble gases are the only atoms with eight valence electrons and therefore tend not to react or combine with other atoms and molecules. This lack of reaction is due to the fact that they are already in their most stable state with a full byte of electrons. Therefore, other atoms with a full byte are called the “noble gas configuration”. Speaking of exceptions to the byte rule, apparently, someone made XeF2 in a sophisticated lab. Xenon is a noble gas and should not bind. And yet, he did, apparently twice. The byte rule is a chemical rule of thumb that reflects the theory that elements of the main group tend to bond so that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas. The rule applies in particular to carbon, nitrogen, oxygen and halogens; In general, however, the rule applies to block S and block P of the periodic table. Other rules exist for other elements, such as the Duplet rule for hydrogen and helium or the 18-electron rule for transition metals. Although stable odd electron molecules and hypervalent molecules commonly learn to violate the byte rule, ab initio molecular orbital calculations show that they largely obey the octet rule (see Three-electron bonds and hypervalent molecules below).
The octet rule prescribes a certain placement of electrons on the orbitals of the atomic nucleus. It also determines whether electrons are added or lost by chemical reactions and measures the chemical reactivity of atoms based on their specific electronic configuration. A sodium atom has a single electron in its outermost electron shell, with the first and second layers again filled with two and eight electrons, respectively. To remove this external electron, only the first ionization energy, which is +495.8 kJ per mole of sodium atoms, requires a small amount of energy. In contrast, the second electron is located in the deeper second electron shell, and the second ionization energy required for its removal is much larger: +4562 kJ per mole. [2] Thus, in most cases, sodium forms a compound in which it has lost a single electron and has a complete outer shell of eight electrons or byte. The byte “rule” is convenient and resembles a “rule of thumb.” It is very useful to quickly add volances with Lewis point clouds and count the valence up to 8. Most of the reactions and compounds you will be looking at probably contain elements such as C, H, O, N, Si, Fe, K, P, Ca, F, Na, etc. In 1916, Lewis wrote his “rule of eight” and the cubic atomic model based on Abegg`s rule. In 1919, Irving Langmuir clarified all these concepts and renamed them “byte theory” and “cubic octet atom”. “Byte theory” is also called “byte rule”. Chlorine dioxide is special because it does not follow the byte rule.
The odd number of electrons means that there must be an unpaired electron. This unpaired electron explains the relatively high reactivity of ClO2. Applications of chlorine dioxide therefore include industrial oxidants and disinfections for drinking water and food. The U.S. Food and Drug Administration describes the production and application of this fairly common chemical in 21CFR173,300. Failure to comply with the byte rule does not render chlorine dioxide bad, scarce or useless. It is a fairly common, important and useful chemical. For noble gases, there are other exceptions to the byte rule. Note that helium (He) is noble. It is element number 2 with only 2 electrons, so it cannot have a byte of 8 electrons. Nevertheless, helium is noble, and elements close to helium in the periodic table are stabilized with 2 electrons (not a byte of 8).
What is really important is an electronic configuration like a noble gas. The byte rule and the number 8 are secondary. The valence electrons of hydrogen act like helium, element number 2. There is 1 hydrogen valence electron and H forms 1 bond. The simple logic is that 1 + 1 = 2 for hydrogen. Helium and hydrogen are exceptions to the byte rule, and some say the “duo rule” applies. H and He are stabilized with 2 electrons, not with one byte. (Duo means 2). Therefore, this article provides a brief explanation of the byte rule as well as its exceptions. To learn more about concepts related to chemical bonds such as hybridization, register with BYJU`S and download the mobile app to your smartphone. The valence electrons can be counted with a Lewis electron point diagram, as shown on the right for carbon dioxide. The electrons shared by the two atoms in a covalent bond are counted twice, once for each atom.
In carbon dioxide, each oxygen shares four electrons with the central carbon, two (in red) with the oxygen itself and two (in black) with the carbon. The four electrons are counted in both the carbon byte and the oxygen byte, so both atoms obey the octet rule. The octet rule is also known as the rule of eight, electron valence theory, or valence octet theory. Byte theory states: The atoms or elements that follow the byte rules are the main elements of the group, which are carbon (C), oxygen (O) and nitrogen (N). The elements of the p and s blocks follow the byte rule with the exception of helium, hydrogen and lithium (Li). Metals such as sodium or magnesium also obey the byte rule. Common electrons meet the valence requirements of the two bonded atoms. Thus, it can be determined that the oxygen atoms and the carbon atom have a byte configuration in the CO2 molecule. Solution: Carbon and nitrogen follow the byte rule and hydrogen has two electrons. We have a total of 10 electrons to work with.
A good starting point is to give nitrogen three bonds to carbon. The carbon then needs another bond that corresponds to the bond that hydrogen needs. Structure resolved! The energy required to transfer an electron from a sodium atom to a chlorine atom (the difference between the 1st sodium ionization energy and the electron affinity of chlorine) is low: +495.8 − 349 = +147 kJ mol−1. This energy is easily balanced by the energy of the sodium chloride lattice: −783 kJ mol−1. [3] This concludes the explanation of the byte rule in this case. The chemical behavior of the main elements of the group can be predicted using the byte rule. Indeed, the rule only affects the electrons `s` and `p`, the byte corresponding to an electronic configuration ending in s2p6. These elements tend to form links to obtain stable byte configurations. Our editors will review what you have submitted and decide if the article needs to be revised.
By the end of the 19th century, it was known that coordination compounds (formerly called “molecular compounds”) were formed by the combination of atoms or molecules in such a way that the valences of the atoms involved were apparently filled. In 1893, Alfred Werner showed that the number of atoms or groups associated with a central atom (the “coordination number”) is often 4 or 6; Other coordination numbers up to a maximum of 8 were known, but less frequent. [8] In 1904, Richard Abegg was one of the first to extend the concept of coordination number to a concept of valence, in which he distinguished atoms as electron donors or acceptors, resulting in positive and negative valence states that closely resemble the modern concept of oxidation states. Abegg found that the difference between the maximum positive and negative valences of an element under his model is often eight. [9] In 1916, Gilbert N. Lewis referred to this discovery as Abegg`s rule and used it to formulate his cubic atomic model and the “rule of eight,” which began to distinguish between valence and valence electrons. In 1919, Irving Langmuir refined these concepts by renaming them “cubic byte atom” and “octet theory”. [11] “Byte theory” evolved into what is now known as the “byte rule.” Here are some examples of problems that explain how electrons are counted to determine if an atom follows the byte rule. The molecules are drawn with Lewis point structures. Why do we need eight electrons? What rule does he follow? And what is the byte rule that atoms normally follow in bonding? This article provides answers to these questions.