1. how is a pair of molecular orbitals formed?
by the overlap of two atomic orbitals from the same atom
by the reproduction of a single atomic orbital
by the splitting of a single atomic orbital
by the overlap of two atomic orbitals from different atoms

Molecular orbitals are formed by the overlap of two atomic orbitals from different atoms.

Explanation:

A pair of molecular orbitals are formed by the overlap of two atomic orbitals from different atoms which are forming a molecule.

There are two parts of a molecular orbital, bonding and anti-bonding molecular orbital.

The bonding molecular orbital (BMO) are formed by the constructive interference of the atomic orbitals.

The anti-bonding molecular orbital (ABMO) are formed by the destructive interference of the atomic orbitals.

can you give more detail in the question? ill answer it in the comments once you post the story

Explanation: