Chemistry Chapter 6 Review: Periodic Table & Elements

38. If element number 119 is discovered, which group of elements would it be in? What would you predict about its physical and chemical properties?

Element 119 would be an alkali metal. It would have a large atomic radius with a low ionization energy and electron affinity. It would easily lose its one valence electron, making it highly reactive. It would be a soft, low density metal.

37. If element number 119 is discovered, where would it be located on the periodic table? What would you predict about its atomic structure?

Element 119 would be located in Group 1 and Period 8, just below francium. It should have electrons in eight energy levels with its one valence electron in energy level 8. It would have a similar electron configuration as francium. Its noble gas notation would be [Og]8s1.

13. Why are elements in groups?

Elements in groups have similar electron configurations. Similar electron configurations result in similar physical and chemical properties. (page 133)

26. Explain why atomic radius changes as it does along rows and columns of the periodic table.

From left to right across a row, each element adds an electron and a proton. This increases the nuclear charge, increasing the electrostatic attraction on all the electrons and decreasing the atomic radius. From top to bottom within a column, another electron shell is added. The atom increases in size due to the additional shell and the fact that the outermost electrons are shielded significantly from the nuclear charge by the inner electrons. (page 127-28)

34. Explain why hydrogen is often considered a group by itself.

Hydrogen has an electron configuration and, therefore, chemical properties similar to both Group 1 and Group 17 elements, but it is a gas-a physical property of nonmetals. (page 134)

11. Describe the trends in ionization energy.

Ionization energy increases from left to right across a period and decreases from top to bottom within a column. (page 129)

4. Why were several elements in odd places in Mendeleev's table? How was the problem corrected?

Mendeleev ordered the elements in the periodic table by atomic mass. Moseley corrected the problem by arranging the elements by their atomic numbers. (page 119-20)

25. You are working on a project that needs an element that is a solid with high density and conductivity but that is also relatively nonreactive. Where on the periodic table would you look? Explain.

Metals tend to be solids with high density and conductivity. The metals in the middle of the periodic table tend to be less reactive than metals toward the left side of the periodic table. Therefore, the best options would be transition and post transition metals. (page 124, 138, 140)

15. What is unusual about most of the inner transition metals in the actinoid series?

Most of the actinoid metals are found only as of the products of manmade nuclear reactions in bombs and reactors. Students may also say that they are all radioactive. (page 139)

32. Do you think that electronegativity is the main property that determines how strongly an isolated neutral atom holds on to its valence electrons? Defend your answer.

No. Pauling determined electronegativity on the basis of how strongly atoms in molecules, not in isolation, attracted and held electrons. (page 131)

29. If an element's first ionization energy is large, what can you predict about its atomic radius, electron affinity, and electronegativity?

The element would tend to have a smaller atomic radius, a higher electron affinity, and a larger electronegativity (excluding noble gases). (page 127-32)

24. Why is the periodic table arranged as it is?

The periodic table is a model of both atomic structure and properties of elements. Its arrangement reflects the structure of atoms. The rows of the table represent the energy levels in the atoms. The columns are related to the electron configuration of the atoms. Because the electron arrangement determines chemical properties, the columns are also representative of those properties. The various blocks of elements represent the energy (s, p, d, and f) sublevels that are occupied by the electrons in the atom. The arrangement also relates to the physical and chemical properties that are a result of the internal structure of the atoms. The periodic table is a model that represents the designed structure of matter itself. (page 122-23)

21. What information can be found on the periodic table?

The periodic table tells us an element's name, symbol, the number of its protons (atomic number), its atomic mass, and its electron configuration. From this we can determine the number of electrons in an element's neutral atom, the highest occupied energy level for electrons in its ground state, its occupied energy sublevels of electrons, its probable charge on an ion, its general type (metal, nonmetal, or metalloid), its relative atomic radius, its ionic radius, its electronegativity, its electron affinity, and its reactivity. (page 121)

7. (True or False) The shape and arrangement of the periodic table directly reflect the electron structure of the atoms composing the elements.

True (page 122-23)

5. Give two names for horizontal rows in the periodic table.

periods, series (page 122)

6. What are groups?

the elements found in a column on the periodic table (page 122)

3. What convinced the scientific community that Mendeleev's periodic table worked? How does this illustrate one aspect of a good scientific model?

A few years after Mendeleev published his periodic table, a scientist discovered one of the unknown elements predicted by a gap in Mendeleev's table. This dis- covery vindicated his work. Workable scientific models make accurate predictions. (page 119)

1. Why were Döbereiner's triads replaced?

As more elements were discovered, scientists recognized that more than three elements had similar characteristics. (page 118)

19. Summarize the development of the periodic table.

As more elements were discovered, the number of elements required some type of organization. Initially, scientists created lists of the elements. They began to see patterns in their lists. Döbereiner found sets of three elements with similar properties. Newland expanded on the concept of groups of elements with similar properties, and he noticed that these properties repeated every eighth element when the elements were ordered by atomic mass. Mendeleev advanced the concept of periodicity by including empty spaces in his periodic table where he predicted that newly discovered elements would eventually fit. Moseley developed a technique to determine the number of protons (the atomic number) in each element. The periodic table was then rearranged on the basis of atomic number. (page 117-21)

33. Periodic trends are models of the properties of atoms of different elements. How well do the trends in atomic radii predict the radii of atoms? What does this say about the workability of this model?

Atomic radii almost always follow the expected pattern, and so the trend is a good predictor of atomic radii. The peri- odic table is a model of the properties of elements according to atomic structure. In this case, it is a very workable model. (page 127-32)

16. Which Group 14 element is prominent in chemistry as well as in other branches of science? Explain.

Carbon has the greatest prominence in chemistry because it is the basis of biochemistry and organic chemistry. The carbon-12 isotope is the basis for defining the atomic mass unit. (page 142)

30. Why are cations smaller than the neutral atoms of the same element?

Cations form by removing electrons from the neutral atom. This creates a charge imbalance that increases the attractive force from the nucleus, resulting in the remaining electrons being pulled closer to the nucleus. Additionally, in some instances the entire outer electron shell is removed, resulting in a smaller radius. (page 128)

9. How do the sizes of cations and anions compare with their corresponding neutral atoms?

Cations tend to be smaller and anions tend to be larger than their respective neutral atoms. (page 128)

39. Why do you think chlorine was isolated before fluorine? Use the ethics box below to answer Question 40.

Chlorine has a lower electronegativity than fluorine, making it less active. It is, therefore, easier to isolate than fluorine.

27. Why does electron affinity change as it does along rows of the periodic table?

Electron affinity is the change in energy when an electron is added to an atom and is a function of the strength of attraction on the electrons. Atoms farther to the right are smaller, so there is an increased attraction on the electrons. More energy is released from the atoms farther to the right on the periodic table. (page 130)

12. Describe the trends in electronegativity.

Electronegativity generally increases from left to right across a period and increases from bottom to top within a column. (page 131)

23. In general, how do the electron configurations of the elements in a row in the periodic table compare?

The atoms of the elements in a row (period or series) generally increase the number of valence electrons from left to right across a row. (page 122)

20. Describe two benefits of the periodic table.

The table collects large amounts of information about all the elements in a small space, connects the properties of elements with the structure of the atoms themselves, and provides a system to make predictions about the properties of an element on the basis of its position in the table. (Accept any two.) (page 117)

40. Use the ethical decision-making process outlined in Chapter 3 (pages 74-75) to explain how a Christian should respond to balancing the need for rare materials with the potential harm to the environment and people.

There are a number of proposed processes to obtain these elements. One is to obtain them from phosphate wastes. There is concern that this process will do harm to the environment. Another option is to obtain these elements from uranium and thorium ores. But there is concern that this will result in exposing the environment and people to radiation. A third potential source is to refine the elements from coal and coal byproducts. With this process there is the concern of the environmental impact associated with coal mining. The Bible makes it clear that we are to meet the needs of others while being good stewards of the earth. Stewardship incorporates the two aspects of using the resources that the earth provides while not unnecessarily harming the planet. One approach would be to forgo any process for obtaining these materials because of the potential harm to people and the environment. This outcome would negatively impact people who depend on these rare-earth elements. Another approach would be to process these elements regardless of the negative effects on people and the environment. This approach is directly contradicted by biblical principles. A third option is to investigate these methods and use those that can provide the needed supply but make modifications to protect the environment and people. We can glorify God and be thankful for His provision by recognizing that He has provided an ample supply of these elements. We can demonstrate our love of God and others by meeting their needs while at the same time keeping them from harm and protecting the world they live in.

2. What were the transition metals of Mendeleev's periodic table?

These were elements that didn't seem to fit in with the other groups of elements but had properties similar to each other. (page 119)

31. Which of the stable alkaline-earth metals (Be, Mg, Ca, Sr, and Ba) fit in each of the descriptions? a. has the largest atomic radius b. has the largest ionization energy c. has the largest ionic radius d. has the smallest electronegativity

a. Ba b. Be c. Ba d. Ba (all page 127-32)

35. Of the elements Al, Au, Br, C, Ca, Cl, Cs, F, Fe, H, He, Hg, K, Mg, Na, O, Si, and W, which fit in each of the following descriptions? a. the principal metal found in human bones b. can exist as diamond, graphite, or charcoal c. gaseous at room temperature d. liquid at room temperature e. soft, highly reactive metal f. a constituent of bauxite g. most electronegative element h. a gas with a similar electron configuration as alkali metals

a. Ca b. C c. F, H, He, O d. Br, Hg e. Cs, K, Na f. Al g. F h. H (all page 134-46)

18. Identify the group number for each element group a. halogens b. boron group c. noble gases d. pnictogens e. chalcogens f. alkaline-earth metals g. transition metals h. alkali metals

a. Group 17 b. Group 2 c. Group 18 d. Group 15 e. Group 16 f. Group 13 g. Groups 3-12 h. Group 1 (all page 136-46)

8. Identify the scientist who a. played the lead role in developing the structure of the modern periodic table. b. formulated the concept of triads. c. proposed that elemental properties vary in octaves. d. predicted the existence of several missing elements at the time of his work. e. ordered the periodic table by atomic number. f. devised the commonly used electronegativity scale.

a. Mendeleev (page 119) b. Döbereiner (page 118) c. Newlands (page 118) d. Mendeleev (page 119) e. Moseley (page 120) f. Pauling (page131)

28. Of the elements in Group 13, predict which has (a) the largest atomic radius, (b) the largest electronegativity, and (c) the smallest ionization energy. Explain your predictions.

a. Thallium has the largest atomic radius since it has the greatest number of principal energy levels (n = 6) of any element in the group. Though not naturally occurring, nihonium (n = 7) is also acceptable. b. Boron has the largest electronegativity. Atoms with few energy levels tend to attract electrons strongly because there is less shielding of valence electrons from the nuclear charge. Boron has the fewest energy levels of this group. c. Students will most likely claim that nihonium would have the smallest first ionization energy. This conclusion is understandable according to current periodic trends. In reality, indium and thallium both have lower ionization energy due to their atomic structures. Indium's first ionization energy is the lowest of all in Group 13. Accept either nihonium or indium as the correct answer. (This example demonstrates the limitations of periodic trends as models.) (all page 127-32)

36. Identify each of the following clements by its group and by its period or series. a. cesium b. cerium c. uranium d. calcium e. lithium

a. alkali metal b. lanthanoid c. actinoid d. alkaline-earth metal e. alkali metal (all page 134-46)

10. Identify the term that matches each definition. a. the energy change associated with the formation of an anion b. a measure of an atom's size c. the energy required to remove an electron d. a measure of an atom's ability to attract or hold valence electrons in a molecule

a. electron affinity (page 130) b. atomic radius (page 127) c. first ionization energy (page 129) d. electronegativity (page 131)

22. Name the element that appears at each of the following addresses in the periodic table. a. Period 5, Group 13 b. Period 4, Group 2 c. Period 2, Group 16

a. indium b. calcium c. oxygen (all page 122-23)

17. Which element a. is the most abundant in the earth's atmosphere by volume? b. is the most abundant in the earth's crust by mass?

a. is the most abundant in the earth's atmosphere by volume?: Nitrogen b. is the most abundant in the earth's crust by mass?: oxygen

14. In which group do we find elements that we traditionally think of as metals?

transition metals (page 138)