Answers to Quiz
1. A. More protons pull the outer shell in more tightly, making the atom smaller
2. C. More inner electrons means that there would be more repulsion of the outer shell, making it easier to remove an electron.
3. B. More energy levels (and inner shell electrons) mean more shielding effect.
4. D. Gaining an electron can require energy (groups 2 and 18) or release energy
(almost all other elements). In this case you don't know what the element is.
NOTE: all energy losses and gains are for atoms in the gas phase.
5. B. Big atoms are not as likely to gain electrons. Their affinity for electrons
6. A. Nitrogen has five electrons in its outer shell. You would expect it to
gain 3. (Unless it is combining with something that is more electronegative
than it is).
7. B. Energy is required to add an electron to a noble gas.
8. C. The biggest is the most likely to lose electrons, so it is most metallic.
9. B. Chlorine has 7 electrons in its outer shell, so it forms ions by gaining electrons which make it bigger as an ion.
10. A. Big atoms are not as likely to gain electrons.
11. B. It is difficult to remove electrons from small atoms. Nonmetals tend to have smaller atoms, so they have higher ionization energies.
12. D. Using a series as an example: Atoms get smaller from left to right. As atoms get smaller, all of the other trends get bigger.
13. A. Energy out increases stability.
14. A. Losing electrons always requires energy. If energy is released, an electron had to be gained.
15. B. A positive electron affinity means that energy is required in order to add an electron to an atom. Energy is required to add electrons to the noble gases.
16. B. Adding an electron to an atom may cause a release of energy or an increase in energy, depending on the element. The best answer is "sometimes."
17. B. All of these have the same number of electrons(isoelectronic). Thus, the ion with the fewest protons will be the largest.
18. E. Silicon has 4 electrons in its valence shell. Two atoms of oxygen will be required to accept all four. (Each atom of oxygen gains two).
19. C. Sodium has one valence electron. The second electron to be removed has to come from the next lower energy level.
Electrons in the valence shell come off easily. The big increase in ionization energy comes when electrons are removed from inner energy levels.
20. D. Energy is gained when electrons are removed from atoms, and when electrons are added to groups 2 and 18. You don't know what the element is, so you don't know what happened.
21. Sodium. Sodium loses one electron and phosphorous gains three. It takes three atoms of sodium to combine with one atom of phosphorous.