Which of the following do you expect to be molecular solids?
A. sodium hydroxide NaOH
B. Solid Ethane C2H6
C. Nickel, Ni
D. Solid Silane SiH4
B. and D.
To determine which of the given substances are molecular solids, you need to consider their molecular structures.
Molecular solids are made up of discrete molecules held together by intermolecular forces such as van der Waals forces, hydrogen bonds, and dipole-dipole interactions. Ionic compounds and metallic elements, on the other hand, do not consist of discrete molecules and therefore are not considered molecular solids.
Let's go through each option and analyze the bonding present in each substance:
A. Sodium hydroxide (NaOH): Sodium hydroxide is an ionic compound composed of sodium cations (Na+) and hydroxide anions (OH-). Since it does not consist of discrete molecules, it is not a molecular solid.
B. Solid ethane (C2H6): Ethane, C2H6, is a nonpolar molecular compound consisting of two carbon atoms bonded together with single bonds and six hydrogen atoms bonded to the carbons. The molecules in solid ethane are held together by weak intermolecular forces, making it a molecular solid.
C. Nickel (Ni): Nickel is a metallic element. Metallic elements do not form molecules but form a closely packed arrangement of atoms held together by metallic bonds. Therefore, nickel is not a molecular solid.
D. Solid silane (SiH4): Silane, SiH4, is a nonpolar molecular compound similar to methane (CH4) but with silicon in place of carbon. The molecules in solid silane are held together by weak intermolecular forces, so it is a molecular solid.
Based on the analysis above, the substances that are expected to be molecular solids are:
B. Solid Ethane (C2H6)
D. Solid Silane (SiH4)