Explanation:
A compound formed due to transfer of electron from one atom to another is known as an ionic compound. An ionic bond is always formed between a metal and a non-metal.
For example, when potassium donates its one valence electron to iodine then it results in the formation of potassium iodide compound.
And, a compound formed by sharing of electrons between the combining atoms is known as a covalent compound.
For example, fullerenes are an allotrope of carbon where sharing of electrons takes places within the carbon atoms.
Hence, fullerenes are covalent compounds.
Metallic compounds are defined as the compounds in which metal atoms of one or more elements are bonded to each other.
For example, pure potassium will contains only atoms of potassium element. Therefore, it is a metallic compound.
A molecular solid is defined as a substance in which the atoms are held together by Vander waal forces. Due to which they have low melting point.
Generally, non-polar compounds leads to the formation of molecular solids.
For example, frozen carbon dioxide is a molecular solid.
Therefore, we can conclude that the given species are classified as follows.
- Pure potassium - metallic
- Frozen carbon dioxide - molecular solid
