Question

What are pure orbitals?

Answer 1

Orbitals in terms of chemistry and physics known as wave function, its main function is to describe the characteristics properties of not more than two electrons which are located in the atomic nucleus or system of nuclei as in a molecule.

Complete answer:
An orbital consists of a three-dimensional region in which there is $95\%$ probability of finding an electron. It is basically the combination of numerals and letters which represent specific properties of the electrons associated with the orbitals such as $1s$, $2p$, $3d$, $4f$. Here these numerals are termed as principal quantum numbers that recommend energy levels as well as relative distance from the nucleus. The energy level of $1s$ electron is equivalent to that of a nucleus. The energy level of $2s$ electron is less strongly bound and spends most of its time farther away from the nucleus.
Here $s$, $p$, $d$ and $f$ tell about the shape of the orbital. The $s$ orbital possesses a spherical shape with its centre at the nucleus whereas the $p$ orbital consists of a pair of lobes on the opposite sides of the nucleus, or we can say dumbbell shape. The shapes of the other two are more intricate. Here these letters $s$, $p$, $d$ and $f$ operated to classify spectra which describe the sharp, principal, diffuse and fundamental before the relation between spectra and atomic electron configuration was known.
An atomic orbital which can’t undergo hybridization is termed as pure orbital. Which means those orbitals which don't take part in hybridization are termed as pure orbital.

Note:
The main purpose of the orbital is to depict the probability of finding the location of an electron in a region around an atomic nucleus. Values of the $n$, $l$ and ${m_l}$ quantum numbers describe the energy state of the electron cloud or we can say orbital.