[Chemistry Class Notes] on Shapes of Atomic Orbitals Pdf for Exam

In atomic theory, an atomic orbital is a function that describes the behaviour of an electron in an atom. This is used to find the probability of finding any electron of an atom in a specific region. The term atomic orbital also refers to the physical region or space where the electron can be calculated to be present. 

Each orbital in an atom is distinguished by a unique set of values of the three quantum numbers namely n, l, and m. It corresponds to the electron energy, its angular momentum, its magnetic quantum number. The simple names associated with the shells are s orbital shape, p orbital shape, d orbital shape, and f orbital shapes. These names or shapes together with the value of n are used to describe the electronic configuration of atoms. In chemical bonding shapes of atomic orbitals, they are the basic building blocks of the atomic orbital mode.

Orbital Shapes

In general, terms talking about the shape of orbits of an electron, the number n determines the size and energy of the orbital for a given nucleus. As ‘n’ increases, the orbital size also increases. This makes the size of the atom roughly constant, even as the number of electrons is heavier. 

The single s-orbitals where l=0. They are shaped like spheres. For n=1, it is roughly a solid ball. It is dense at the centre and fades outwardly.

Individual orbitals are often shown independent of each other. The orbitals exist around the nucleus at the same time. The reason for this comparison lies in the explanation that the distribution of kinetic energy and momentum in a matter wave is somewhat predictive. It means that it is assumable where the particle associated with the wave will be. This relationship also indicated that certain key features are observed in both the drum membrane models and atomic orbitals. 

Let us understand this description in detail. The very centre of the drum membrane vibrates strongly, corresponding to all s orbital shapes. This means that the electron is most likely to be in the physical position of the nucleus. It is moving more rapidly at this point, which gives it maximal momentum.

Concept of Different Orbital Shapes and Sizes

Did you realize that not all electrons in an atom have the same amount of energy associated with it? Yes, it is true. 

The amount of energy depends upon its location as to where it is located within an atom. Electrons reside in their energy levels or shells. The shells surround the atom’s nucleus at various distances. Each shell is then subdivided into s,p,d, and f. The shape of spdf orbitals has its unique shape based on the energy levels of electrons.

The s orbital is a spherical shape. It has a nucleus in the centre of the atom. 1s electron is entirely confined to a spherical region very close to the nucleus. The p orbital is dumbbell-shaped. A 2s electron is somewhat related to a larger sphere. A p orbitals are in the shape of a pair of lobes on opposite sides of the nucleus. 3 p orbitals that differ in orientation and 5 d orbital shape. Out of these 4 have a clover shape with different orientations and one amongst them is unique. The p orbitals are in the shape of dumbbells like figures.

There are 7 f orbitals, all are of different orientations. Asking a general question, why do they occupy different orientations?

It is simply because the atom is three-dimensional. The further away the nucleus is from the atom, the more complex shape it will acquire. It acquires a more complex shape because of the energy distribution of electrons.