Unit 3 Periodic Table Homework AP
Directions: For each question, provide your final answer below the question. For math-based answers,
work must be shown on this page or a separate sheet of paper attached to the back of this packet.
Without work, no credit will be given. Check significant figures and units.
1. Use the details of modern atomic theory to explain each of the following experimental observations.
(a) Within a family such as the alkali metals, the ionic radius increases as the atomic number increases.
(b) The radius of the chlorine atom is smaller than the radius of the chloride ion, Cl-.
(Radii: Cl atom = 0.99Å; Cl- ion = 1.81 Å)
(c) The first ionization energy of aluminum is lower than the first ionization energy of magnesium.
(First ionization energies: 12Mg = 7.6 ev; 13Al = 6.0 ev)
(d) For magnesium, the difference between the second and third ionization energies is much larger than the
difference between the first and second ionization energies. (Ionization energies for Mg: 1st = 7.6 ev;
2nd = 14 ev; 3rd = 80 ev)
Ne
2000
F
N
1500
O
first ionization energy (kJ/mol)
1000
Be
C
B
500
Li
0
2. The diagram shows the first ionization energies for the elements from Li to Ne. Briefly (in one to three
sentences) explain each of the following in terms of atomic structure.
(a) In general, there is an increase in the first ionization energy from Li to Ne.
Unit 3 Periodic Table Homework AP
(b) The first ionization energy of B is lower than that of Be.
(c) The first ionization energy of O is lower than that of N.
(d) Predict how the first ionization energy of Na compares to those of Li and of Ne. Explain.
3. Suppose that a stable element with atomic number 119, symbol Q, has been discovered.
(a) Write the ground-state electron configuration for Q, showing only the valence-shell electrons.
(b) Would Q be a metal or a nonmetal? Explain in terms of electron configuration.
(c) On the basis of periodic trends, would Q have the largest atomic radius in its group or would it have the
smallest? Explain in terms of electronic structure.
(d) What would be the most likely charge of the Q ion in stable ionic compounds?
(e) Write a balanced equation that would represent the reaction of Q with water.
(f) Assume that Q reacts to form a carbonate compound.
(i) Write the formula for the compound formed between Q and the carbonate ion, CO32–.
(ii) Predict whether or not the compound would be soluble in water. Explain your reasoning.
Unit 3 Periodic Table Homework AP
Directions: Read the passage below and answer the summary questions that follow in complete sentences.
Element 117 Hints at 'Island of Stability' on Periodic Table
Clara Moskowitz
Scientific American
Physicists have created one of the heaviest elements yet, an atom with 117 protons in its nucleus. This jumbosized atom sits on the outer reaches of the periodic table where bloated nuclei tend to become less and less
stable. Element 117’s existence gives scientists hope, however, that they are getting closer to discovering a
rumored 'island of stability' where nuclei with so-called magic numbers of protons and neutrons become longlived. Elements heavier than uranium (with 92 protons) are not usually found in nature, but they can be forced
into existence in laboratories. The trouble is: the larger an atomic nucleus gets, the more its protons repel one
another with their positive charges, making it, in general, less stable, or more radioactive. Element 117, for
example, has a half-life of about 50 thousandths of a second, meaning that within that time about half of it will
decay into a lighter element. A US–Russian team first created element 117 in 20101 at the Joint Institute for
Nuclear Research in Dubna, Russia. The element is still considered unofficial, and has not yet been formally
accepted and added to the periodic table by the International Union of Pure and Applied Chemistry (IUPAC).
The new appearance of 117, in experiments by the GSI Helmholtz Center for Heavy Ion Research in Darmstadt,
Germany, should help the element gain official recognition. “In contrast to the first discovery, we are a different
team at a different place using a different device,” says Christoph Düllmann, who led the GSI collaboration. “I
think within the scientific community that will change the view on element 117 from an element that has been
claimed to be observed to an element that is confirmed.”
To create 117, with the temporary periodic table placeholder name ununseptium, the researchers smashed
calcium nuclei (with 20 protons apiece) into a target of berkelium (97 protons per atom). The experiment was so
difficult in part because berkelium itself is tough to come by. “We had to team up with the only place on the
planet where berkelium can be produced and isolated in significant quantities,” Düllmann says. That place is the
Oak Ridge National Laboratory in Tennessee, which has a nuclear reactor that can create the rare element with
a half-life of 330 days. It took the facility about two years to build up a large enough stock of berkelium for the
experiment; when about 13 milligrams had accumulated, Oak Ridge scientists shipped it off to Germany for the
next stage of the project. At GSI, researchers accelerated calcium ions to 10% of light-speed and sent them
colliding into the berkelium. If a calcium and berkelium nucleus collided head-on, occasionally the two nuclei
would stick together, fusing to form a new element with a combined total of 117 protons. “We get about one
atom per week,” Düllmann says. The scientists did not observe element 117 directly. Instead, they searched for
its daughter products after it radioactively decayed by emitting alpha particles—helium nuclei with two protons
and two neutrons. “The heavy nuclei makes an alpha decay to produce element 115, and this also decays by
alpha decay,” says Jadambaa Khuyagbaatar of GSI, lead author of a paper reporting the results published on 1
May in Physical Review Letters After a few more steps in this decay chain, one of the nuclei produced is the
isotope lawrencium 266—a nucleus with 103 protons and 163 neutrons that had never been seen before.
Previously known isotopes of lawrencium have fewer neutrons, and are less stable. This novel species,
however, has an astonishingly long half-life of 11 hours, making it one of the longest-lived superheavy isotopes
known to date. “Perhaps we are at the shore of the island of stability,” Düllmann says. No one knows for sure
where this island lies, or even if it exists at all. Theory suggests that the next magic numbers beyond those
known are around 108, 110 or 114 protons, and 184 neutrons. These configurations, according to calculations,
Unit 3 Periodic Table Homework AP
could lead to special properties that allow atoms to survive much longer than similar species. “All existing data
for elements 116, 117 and 118 do confirm that lifetimes increase as one goes closer to the neutron number 184,
says theorist Witold Nazarewicz of Oak Ridge, who was not involved in the study. “This is encouraging.” Super
heavy magic nuclei may turn out to have interesting shapes that confer stability, such as a so-called bubble
configuration with a hole in the middle. “These have never been discovered yet, but the region that is being
explored now is really on the edge of bubble territory,” Nazarewicz says. If an island of stability does exist,
there is no limit to how long its nuclei may last. They could turn out to be stable enough to be found in nature,
albeit in such small quantities that we have not seen them yet. Numerous searches are on for evidence of these
super heavy species already in existence, perhaps having formed through powerful cosmic events such as the
merging of two neutron stars. Although none have been found so far, scientists are holding out hope that
evidence for the island of stability is just around the corner, one way or another.
1. Describe what the author means by the “island of stability.”
2. Explain, using Coulomb’s Law, why elements larger than Uranium are all radioactive.
3. Give a noble gas short cut configuration of element 117.
4. How many valence electrons does the element 117 have? Draw a Lewis structure.
5. Is the decay product Lr-266, paramagnetic or diamagnetic? Use configurations of orbital notations to
justify your answer.