Atomic Orbital vs Hybrid Orbital
The bonding in molecules was understood in a new way with the new theories presented by Schrodinger, Heisenberg, and Paul Diarc. The quantum mechanics came into the picture with their findings. They found that an electron has both particle and wave properties. With this, Schrodinger developed equations to find the wave nature of an electron and came up with the wave equation and wave function. Wave function (Ψ) corresponds to different states for the electron.
Max Born points out a physical meaning to the square of the wave function (Ψ2) after Schrodinger put forward his theory. According to Born, Ψ2 expresses the probability of finding an electron in a particular location. So, if Ψ2 is a larger value, then the probability of finding the electron in that space is higher. Therefore, in the space, electron probability density is large. In contrary, if Ψ2 is low, then the electron probability density there is low. The plots of Ψ2 in x, y, and z axes show these probabilities, and they take the shape of s, p, d and f orbitals. These are known as atomic orbitals. An atomic orbital can be defined as, a region of space where the probability of finding an electron is large in an atom. Atomic orbitals are characterized by quantum numbers, and each atomic orbital can accommodate two electrons with opposite spins. For example, when we write the electron configuration, we write as 1s2, 2s2, 2p6, 3s2. 1, 2, 3….n integer values are the quantum numbers. The superscript number after the orbital name shows the number of electrons in that orbital. s orbitals are sphere shaped, and small. P orbitals are dumbbell shaped with two lobes. One lobe is said to be positive, and the other lobe is negative. The place where two lobes touch each other is known as a node. There are 3 p orbitals as x, y and z. They are arranged in space so that their axes are perpendicular to each other. There are five d orbitals and 7 f orbitals with different shapes. So collectively, following are the total number of electrons that can be resided in an orbital.
s orbital-2 electrons
P orbitals- 6 electrons
d orbitals- 10 electrons
f orbitals- 14 electrons
Hybridization is the mixing of two non equivalent atomic orbitals. The result of hybridization is the hybrid orbital. There are many types of hybrid orbitals formed by mixing s, p and d orbitals. The most common hybrid orbitals are sp3, sp2 and sp. For example, in CH4, C has 6 electrons with the electron configuration 1s2 2s2 2p2 at the ground state. When excited, one electron in the 2s level move to the 2p level giving three 3 electrons. Then the 2s electron and the three 2p electrons mix together and form four equivalent sp3 hybrid orbitals. Likewise in sp2 hybridization three hybrid orbitals and in sp hybridization two hybrid orbitals are formed. The number of hybrid orbitals produced is equal to the sum of orbitals being hybridized.
What is the difference between Atomic Orbitals and Hybrid Orbitals?
• Hybrid orbitals are made from the atomic orbitals.
• Different types and numbers of atomic orbitals are participating in making hybrid orbitals.
• Different atomic orbitals have different shapes and number of electrons. But all the hybrid orbitals are equivalent and have the same electron number.
• Hybrid orbitals normally participate in covalent sigma bond formation, whereas atomic orbitals participate in both sigma and pi bond formation.