What type of solid (network, metallic, Group 8A, ionic, or molecular) will each of the following substances form? a. Kr b. SO 2 c. Ni d. SiO 2 e. NH 3 f. Pt

Interpretation:

           The type of solid formed by the given by compounds has to be identified.

                                  (a) Kr (b) SO2 (c)Ni  (d)SiO2  (e)NH3  (f)Pt

Concept introduction:

• A solid is anything that is firm and stable in shape. Physics and Chemistry do provide clear cut explanation for the structure of solids. The firm and dense nature of solids is due to the strong intermolecular forces between their components.

• On the basis of the arrangement of the components in a solid, there are two distinct types of solids - crystalline solids and amorphous solids. These two types differ in the arrangement of their respective components and so in their properties.

• Crystalline solids have their own sub-classification. The types of solids can be summarized as follows –

                                                             Figure 1

• Crystalline solids have well-defined regular, compact, orderly arrangement of their components of very long range order. They are termed as true solids. Ionic solids, molecular solids, covalent solids and metallic solids are the types of crystalline solids. 

• In ionic solids, ions of opposite charges are bind together by electrostatic force and are neatly stacked to form a regular and well-defined structure. Example: KCl , Rutile.

• Amorphous solids lack such well defined arrangement of its components instead disordered or random arrangement does exist in them. They are termed as pseudosolids or super cooled liquids. Example: Glass, Wood etc.

• In molecular solid, molecules are arranged in such a fashion and in metallic solid metal atoms are arranged in such a manner. Example: Ice for molecular solid and almost all metals and alloys for metallic solids.

• Non-metal atoms held together by weak London dispersion forces form atomic solids. Example: Solid Argon, Solid Krypton.

• In Covalent solids the components are atoms bonded by covalent bond repetitively and thus forms huge network form of solid. Network solids are widely formed by group 14 elements and its compounds. Example: Diamond, Amethyst.

• All these types of solids differ in their respective intramolecular as well as intermolecular forces. As a result, each type of solid has unique properties.

(a) Kr

     Analyze the bonding properties of Krypton and the intermolecular force exist in it.

  Krypton is an inert gas. It exists as individual atoms forming group 8A atomic solids.

          Inert gas elements, also known as group 8A elements exist as individual atoms. They are not very reactive to involve in bond information due to their completely filled valence shells. Thus, almost all the group 8A elements exist as gaseous atoms. When subjected to low temperature they get liquefied or solidified even. Still, these elements are not involved in bonding and exist in atomic state in their solid structure. At low temperature London dispersion forces become stronger in them and solidify the gaseous Krypton. Thus Krypton forms Atomic solids.

(b) SO2

     Analyze the type of bonding and the type of intermolecular force in SO2

     SO2 is a polar covalent compound. It has London dispersion forces and dipole-dipole forces.

      ​ SO2 is a polar covalent compound.  Polar covalent molecules tend to exist as dipoles due to the asymmetric distribution of electrons between the atoms. London dispersion force exists in all type of covalent compounds irrespective of polarity. Therefore the intermolecular forces exist in them are London dispersion force and dipole-dipole force. Being a polar covalent compound ​ SO2 forms Molecular solid.

(c)Ni

    Analyze the bonding nature of Nickel