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.

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o