Question

Iodine crystals are
(a) Metallic solid
(b) Ionic solid
(c) Molecular solid
(d) covalent solid

Answer 1

Hint: To know under which category of solids, these iodine crystals fall, you should know about these metallic, ionic, molecular and covalent solids and then, we can easily categorize the iodine crystals. Now answer the statement.

Complete answer:
 First of all, let’s discuss what are metallic solids, ionic solids and covalent solids. We will discuss these in the tabular form as it is an easy way to understand it.

Type of solid	Constituent particles	Bonding/ attractive forces	Examples
1. Molecular solids: They are divided into the following three types as:(a) Non-polar solids(b) Polar solids(c) Hydrogen bonded solids	These consist of small covalent molecules.It consists of nonpolar molecules ,atoms or noble gases like solid argon, hydrogen etc. It consists of polar molecules.It consists of molecules in which the hydrogen is bonded to fluorine, nitrogen or oxygen atoms.	Molecules are held by weak dispersion or London forces.Molecules are held by dipole-dipole interactions.Molecules are held by the hydrogen bonding.	$Solid\text{ }Ar, C{{O}_{2}},{{H}_{2}},{{I}_{2}}$etc. $HCl, S{{O}_{2}}$ etc.$Ice\left( {{H}_{2}}O \right)$
2. Ionic solids	It consists of the positive and negative ions.	Ions are held together by the strong electrostatic forces.	$NaCl, MgO, BaO, Ca{{F}_{2}},ZnS$ etc.
3. Metallic solids	It consists of positive ions in a sea of delocalized electrons.	Ions are held together by metallic bonding	$\begin{align} & metals\text{ }like\text{ }Cu, Ag, Fe\text{ }and \\ & alloys \\ \end{align}$
4. Covalent solids	It consists of atoms.	Atoms are held together by covalent bonding.	$Si{{O}_{2}},SiC, C\left( diamond \right)$ etc.

So, from this above table , it is clear that iodine crystals are molecular solids.

Hence, option(c) is correct.

Note: Graphite is a covalent solid but it is soft and a good conductor of electricity. It is so because of its typical structure having delocalized pi electrons in hexagonal rings which are free to move.