Author: misamaliraza94
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Hydroboration/Oxidation of Alkenes
When alkenes are treated with borane (BH3) in the presence of hydrogen peroxide or sodium hydroxide, an alcohol is obtained as the final product. In this electrophilic addition reaction, the boron atom acts as an electrophile. This reaction does not obey Markovnikov’s rule and can, therefore, be classified as an anti-Markovnikov reaction.
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Examples
The Hydration of Alkenes When alkenes are treated with certain aqueous acids (usually sulfuric acid), the resulting electrophilic addition reaction yields an alcohol as the product. The regioselectivity of such reactions can be predicted by Markownikoff’s rule. Therefore, these reactions can be classified as Markovnikov reactions. In the hydration of alkenes, the H+ ion acts as an electrophile…
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What is the Mechanism Behind Markovnikov`s Rule?
To understand this mechanism, let us consider the same example illustrated earlier, i.e. the addition reaction of hydrobromic acid with propene. The Mechanism of Markovnikov’s rule can be broken down into the following two steps. Step 1 The alkene is protonated and it gives rise to the more stable carbocation as shown below. From the illustration…
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Markovnikov`s Rule
Markovnikov’s Rule, also known as Markownikoff’s rule, can be used to describe the outcome of some chemical addition reactions. The Russian chemist Vladimir Vasilyevich Markovnikov first formulated this rule in 1865. What is Markovnikov’s Rule? When a protic acid (HX) is added to an asymmetric alkene, the acidic hydrogen attaches itself to the carbon having a…
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Writing the Electron Configuration of Nitrogen
The element nitrogen has 7 electrons (since its atomic number is 7). The electrons are filled into the 1s, 2s, and 2p orbitals. The electron configuration of nitrogen can be written as 1s22s22p3
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Electronic Configuration using the Aufbau Principle
Writing the Electron Configuration of Sulphur The atomic number of sulphur is 16, implying that it holds a total of 16 electrons. As per the Aufbau principle, two of these electrons are present in the 1s subshell, eight of them are present in the 2s and 2p subshell, and the remaining are distributed into the…
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Exceptions
The electron configuration of chromium is [Ar]3d54s1 and not [Ar]3d44s2 (as suggested by the Aufbau principle). This exception is attributed to several factors such as the increased stability provided by half-filled subshells and the relatively low energy gap between the 3d and the 4s subshells. The energy gap between the different subshells is illustrated below. Half filled subshells feature…
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Salient Features of the Aufbau Principle
According to the Aufbau principle, electrons first occupy those orbitals whose energy is the lowest. This implies that the electrons enter the orbitals having higher energies only when orbitals with lower energies have been completely filled. The order in which the energy of orbitals increases can be determined with the help of the (n+l) rule,…
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Aufbau Principle
What is the Aufbau Principle? The Aufbau principle dictates the manner in which electrons are filled in the atomic orbitals of an atom in its ground state. It states that electrons are filled into atomic orbitals in the increasing order of orbital energy level. According to the Aufbau principle, the available atomic orbitals with the…
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FAQs
What is Gay Lussac’s law formula? The law of Gay-Lussac is a variant of the ideal gas law where the volume of gas is held constant. The pressure of a gas is directly proportional to its temperature while the volume is kept constant. P / T = constant or Pi / Ti = Pf /…