Question

The probability of finding an electron in an orbital is approximately:
(A) 95%
(B) 50%
(C) 60%
(D) 25%

Answer 1

Hint: Orbitals are those spaces in which there is maximum probability of finding an electron. Thus, the probability of finding the electron at any point in space will never be zero. By the quantum mechanical approach of the orbitals, we would be able to calculate the probability of finding an electron in an orbital.

Complete answer:
- Let's refresh our concepts about orbitals. As we know, an orbital can be defined as the three dimensional description of the most likely location of an electron around an atom. Or in other words orbital is the space in which there is maximum probability of finding an electron.
- When bonds are being formed between atoms in a molecule, the orbitals are being combined. As we recall, there are mainly four types of orbitals that we are familiar with such as s, p, d and f orbitals. There are some combinations of orbitals within each shell of an atom.
- In terms of quantum mechanics, an atomic orbital can be defined as the mathematical function describing the wave-like behavior and location of an electron in an atom and this function is used to calculate the probability of finding any electron of an atom in any specific region around the atom's nucleus or in orbitals.
- According to the free rotator in simple quantum mechanics there is a nonzero probability of finding a particle (particle in a box) anywhere in the coordinate system. This means that we need to define an arbitrary cutoff point if we want to display anything at all. Most of the time people will choose a cutoff value of 95 % and will draw a line around the entire area inside of which the electron has a 95 % chance of appearing.
- From the above discussion it’s clear that an electron orbital is most commonly defined as the radius of the sphere that encloses 95 % of the total electron probability and the probability of finding an electron in an orbital is approximately 95%.

Therefore, the correct option is A, 95%.

Note: Keep an idea in mind about nodes also. Nodes are those spaces where the probability of finding an electron is very low. Also, atomic orbitals can be uniquely defined by a set of integers known as quantum numbers and they are Principal Quantum Number(n) , the Azimuthal Quantum Number(l), the Magnetic Quantum Number(${{m}_{l}}$) and the Spin Quantum Number (${{m}_{s}}$).