Which formula represents a molecular compound?
(1) Kr 3) N2O4
(2) LiOH (4) NaI
How do you know?
Ionic compounds (LiOH and NaI) exist as ions, Kr is a monoatomic element. N2O4 is a covalent compound and exists as the molecule.
Unfortunately, Dr.Bob didn't answer the question. It is generally true (not always), but elements close to each other on the periodic chart, like O and N, particularly non-metals form molecular compounds. Moreover, the question is tricky. In the gas phase at very high temperature, LiOH and NaI also would be molecular compounds.
To determine which formula represents a molecular compound, we need to understand the characteristics of molecular compounds. Molecular compounds are made up of nonmetals bonded together through covalent bonds.
Looking at the given options:
(1) Kr: Kr is the chemical symbol for krypton, which is a noble gas, not a nonmetal. Therefore, it does not represent a molecular compound.
(2) LiOH: Li is the chemical symbol for lithium, which is a metal. Hence, this compound represents an ionic compound, not a molecular compound.
(3) N2O4: This formula represents a molecular compound. It consists of nitrogen (N) and oxygen (O), both of which are nonmetals bonded together through covalent bonds. Therefore, N2O4 is a molecular compound.
(4) NaI: Na is the chemical symbol for sodium, which is a metal. Similar to option (2), this compound represents an ionic compound, not a molecular compound.
So, the correct answer is (3) N2O4 because it represents a molecular compound.