ENME 3400
A2 Chapter 2: Atomic Structure and Bonding
Due:
Alenzi, Faisal
Perfect score: 200 points
See Calendar
Essay Questions P1 through P7
Answer the following questions. Using MSWord or equivalent, edit this document and enter your
response to each question making space as needed immediately after the question as shown.
Prob. 1 (10 pts.)
In your own words: What is an isotope?
Enter your response to P1 here:
Prob. 2 (10 pts.)
In your own words: Cite two important additional refinements that resulted
from the wave-mechanical atomic model.
Enter your response to P2 here:
Prob. 3 (10 pts.)
Cu+ and Ba2+.
In your own words: Give the electron configurations for the following ions:
Enter your response to P3 here:
Prob. 4 (10 pts.)
Br-, and O2-.
In your own words: Give the electron configurations for the following ions:
Enter your response to P4 here:
Prob. 5 (10 pts.)
In your own words: Is the 1s22s22p63s23p6 electron configuration an
inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your
choices.
Enter your response to P5 here:
Prob. 6 (10 pts.)
In your own words: Offer an explanation as to why covalently bonded
materials are generally less dense than ionically or metallically bonded ones.
Enter your response to P6 here:
Prob. 7 (10 pts.)
In your own words: Explain why hydrogen flouride (HF) has a higher
boiling temperature than hydrogen chloride (HCL), even though HF has a lower molecular
weight.
Enter your response to P7 here:
Formula Problems: P8 through P13
Solve the following problems. Enter numerical result and units in space provided below. Express
results to three or more significant figures. Create clear understandable images of any supporting
hand-written work using a camera or scanner.
Prob. 8 (20 pts.)
Madeitupnium has six naturally occuring isotopes: 0.14% of 290Ma with
an atomic weight of 289.52 amu; 3.2% of 292Ma with an atomic weight of 291.52 amu; 6.08% of
294 Ma with an atomic weight of 293.52 amu; 6.69% of 296Ma with an atomic weight of 295.52
amu; 4.1% of 298Ma with an atomic weight of 297.52 amu; and 79.93% of 300Ma with an
atomic weight of 299.52 amu. Calculate the average atomic weight of Ma.
MW AVE = __________________
Prob. 9 (20 pts.)
An element has two naturally occurring isotopes, isotope 1 with an atomic
weight of 130.13 amu and isotope 2 with an atomic weight of 127.133 amu. If the average
atomic weight for the element is 129.131 amu, calculate the fraction of occurrences of these two
isotopes.
f1 = _______________
f2 = _______________
Prob. 10 (20 pts.) A component is composed of 0.026 moles of zinc and 0.0811 moles of
platinum. Determine (a) total mass of the component (b) weight % of zinc.
(a) Mass: __________
(b) wt%: _____________
Prob. 11 (20 pts.) A relic having a mass of 320 g is known to contain 60.2 wt. % silver and 39.8
wt. % nickel. Determine the atomic percentage of silver in the relic.
Atomic %: _____________
Prob. 12 (25 pts.) The magnitude of the attractive force between two ions, A1+ and B1- at
equilibrium is 10E-9 N. Determine (a) the interionic distance, (b) the ionic radius of B1- if that
for A1+ is 0.078895 nanometers, (c) the magnitude of the repulsive force between the two ions
at this position, (d) the value of the Coulomb's constant b and (e) the minimum potential energy
of the bond. Assume n = 9 in Coulomb’s Law. DON’T FORGET UNITS!!!
(a) Interionic distance: ______________
(b) Ionic radius of B: ________________
(c) Magnitude of Force: _____________
(d) Coulomb’s b: _______________
(e) Emin: ___________________
Prob. 13 (25 pts.)
For each of the following fictitious compounds, use Pauling’s equation to
predict the percentage ionic character. NOTE: THE ANSWER KEY IS BASED ON THE TABLE
OF ELECTRONEGATIVIES included in the ZIP folder (AA_Electronegativities of Select
Elements.PDF). Use any other source at your own risk!
(a)
Mg2Bi _________
(b)
RaSn3 ___________
(c)
MgPb3 ________
(d)
BaS3 ___________
(e)
MgSn3 ________