SCT 152-2 Properties of Matter – Assignment 2
1. The physical properties of materials are predicted based on the knowledge of the
interatomic forces and bonding energies that bind the atoms together.
a. Draw a schematic diagram showing the dependence of potential energies with the
interatomic separation for a polymeric material and diamond. Both curves should
be in the same diagram.
b. The net potential energy
between two adjacent ions is sometimes represented
by following equation,
where is the inter-ionic separation and , and are constants whose values
depend on the specific material.
Derive an expression for the bonding energy
in terms of the equilibrium interionic separation using the following procedure.
i.
Differentiate
with respect to and set the resulting expression equal to
zero.
ii. Obtain an expression for in terms of , and .
iii. Determine the expression for
by substituting above constants.
c. Three different types of primary bonds found in solids are ionic, covalent and
metallic. Describe each type using the involvement of the valence electrons and
the electronic structure of the constituent atoms.
2.
a. Materials are mainly classified as solid, liquid and gas. Describe briefly each state
according to their density, fluidity and compressibility.
b. According to the nature and behavior of solid state materials, they show different
physical and chemical properties.
i.
What is the difference between physical and chemical properties of materials?
ii.
Write four (04) examples of physical changes of solids that we find in day
today life.
c. Carbon can be found as graphite and diamond. Describe briefly their properties using
atomic structure and interatomic bonding.
d. The distribution of electrons around the nucleus can be described using different
models.
i.
What is the main difference between “Bohr model” and “Electron cloud
model”?
ii.
Draw a schematic diagram for the probability of electron distribution of
hydrogen atom using above two models.