Which of the following phenomena will occur when two atoms of the elements having the same spin of electron approach for bonding?
A. Orbital overlap will not occur
B. Bonding will not occur
C. Both A and B are correct
D. None of the above

Hint:Electron spin is a quantum property of electrons. It is a form of angular momentum. The electron can spin in two directions.

Complete step by step answer:
The spin up and spin down direction corresponds to the clockwise and anticlockwise direction. The numerical value for these spins is equal to 1/2, followed by a positive and negative sign, depending upon the direction in which the electron is spinning.
While assigning electrons to orbitals, we need to follow a set of three rules. These rules are:
 1. Aufbau Principle, which states that the orbitals having lower energy are filled first and those having higher energy are filled afterwards.
 2.Pauli-Exclusion Principle, states that, in an atom or molecule, it is not possible to accommodate two electrons which have the same set of four electronic quantum numbers. An orbital can accommodate a total of only two electrons, and these two electrons must have opposite spins.
3. Hund's Rule states that if two or more degenerate orbitals are available, one electron goes into each until all of them are half full before pairing up.
When two atoms having the same spin of electron approach for bonding, the orbital overlap will not occur because the electrons having the same spin are violating the above-mentioned rules. No overlapping means no bond formation.
If two atoms having opposite spin are made to approach for bonding, then their orbitals will overlap and thus bond formation will take place.

So, the correct option is C.

Additional information: In total, there are four different types of orbitals, depending on their shape. These are designated as s, p, d and f.

Note:
The electron spin theory considers the electron as a quantum particle, instead of a simple sphere as considered in classical theory. This theory states that electron spin influences properties like magnetic properties of an atom.