HW1 MSE 250

MSE 250 - Homework Assignment 1

1- For the following elements; O, P, S, Br, Mg, Al, Si, Ti, Cr, Fe, Cu, Zn:
a) Write the outer shell electron configuration in spdf notation using the noble gas to indicate the
inner shell electrons, e.g., Sodium (Na): (Ne) 3s
1
b) For the most stable oxidation state, indicate the cation/anion charge and the outer shell
electron configuration, e.g., Sodium: Na
1+
(He)2s
2
2p
6

c) Generalize the differences between metals and non-metals and determine if these elements are
metals, nonmetals, or metalloids.
2- For the three types of primary bonds; ionic, covalent, and metallic:
a) Describe these bonds as directional or non-directional and the mechanism that attracts the
atoms to each other.
b) List three materials properties that are indicators of high bond strength.
c) For the elements in the fourth period from K to Ga, graph the melting points of the pure
elements. Explain the variation in melting points based on the bonding between the atoms and
their electron configurations.
3- For the following materials, characterize them as metals, ceramics, polymers or
semiconductors and describe their chemical bonding. For mixed ionic/covalent or
covalent/ionic, calculate the percentage of ionic character using the electronegativity differences
between the atoms.
Alumina Al
2
O
3

Aluminum
Steel (Fe-C)
Silicon
Polyethylene
Tungsten Carbide (WC)
Polyvinylchloride (PVC)
Titanium