1. Fall 2017 Exam III 1. e 9. e 16. (next slides)
2. c d 17. (next slides)
3. b d
4. a d
5. b a
6. b a
7. e c
8. c  

2. 16.
(S-2,18e-):1s22s22p63s23p6
Cl-, K+, Ar, Ca+2 all form an isoelectronic series with the sulfur ion because they all have the same total number of electrons (18 e-) s

3. 16. c. (continued) First ionization energy is the energy required to remove the outermost electron from an atom. Each of these atoms/ions has the same number of electrons in the same energy levels, so, in order to determine the relative ionization energy, it is necessary to compare the number of protons in each of the substances.
A greater number of protons will result in a greater nuclear attraction on the electrons of the atom, therefore increasing the ionization energy. Therefore, Ca+2 has the greatest ionization energy because it has the greatest number of protons, and S-2 has the lowest ionization energy because it has the fewest protons, and therefore the electrons are not as strongly ‘held’ by the nucleus.

4. 16. d. No – these will not have the same radius
16. d. No – these will not have the same radius. Even though they have the same number of electrons in the same energy level, they have a different number of protons in the nucleus of the atom which means that the nucleus does not exert the same level of attraction on all of the electrons. Therefore, because calcium has 20 protons, it will attract and hold electrons more tightly than any of the other substances, making the radius smaller. The opposite is true for sulfur, which only has 16 protons.

5. 17. D d

6. 17.
SO3 is present as a liquid. Both molecules are nonpolar overall, which means that both exhibit London Dispersion forces. However, SO3 has more overall electrons than CO2 (could also say higher molar mass), which means that its London Dispersion forces are stronger due to the ability to form stronger temporary dipole moments. This means that it takes more energy to break the intermolecular forces. Therefore, SO3 exists as a liquid at room temperature due to its higher boiling point than CO2.