3. In the above molecules, generally the octet rule can not be followed for every atom. When there are too many electrons or two few electrons and the atoms cannot or will not form multiple bonds, which atom in the structure does not receive a complete or has an expanded octet? Explain why only one atom in the structure is affected in these situations.

The octet rule is possible in those atoms which has high number of electrons in their shells.

Explanation:

The octet rule is a type of rule in which the atom has 8 electrons in its outermost shell or valance shell. This rule is not possible for hydrogen and helium because there are very less number of electrons and we know that octet rule needed more number of electrons. Only one atom may be hydrogen or helium is affected in the structure is affected in these situations due to presence of less number of electrons in shells.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).