Periodic Table and Graphs: Trends in a Chemical Property and Trends in a Physical Property

Questions, Page 123:

1) Does either bar graph reveal a repeating, or cyclic, pattern? Describe any patterns you observe.

By looking at both bar graphs side by side, we noticed that the number of atoms added to the element directly correlated to the boiling points (in °K). The more atoms added, the higher the boiling point.

2) Are these graphs consistent with patterns found in your earlier grouping of the elements? Explain.

Yes. We grouped our elements based on the atom's charge. Elements with positively charged ions were generally on the right side of the table-- closer to what we classified as noble gases. Elements with negatively charged ions were put on the left side of the table, with one positively charged ion set away from the rest of the table on the top. Although the modern periodic table organizes those elements that become cations on the left side of the table, we put the elements that became the cations on the right side of the table, closer to the noble gases, due to the closer atomic numbers and element names (or numbers). Even so, our version of the periodic table sort of imitates the modern periodic table. Additionally, we noticed that positively charged ions generally had higher boiling points than those with negative charges.

3) Based on these two bar graphs, why is the chemist's organization of elements called a periodic table?

Based on these two bar graphs, the chemist's organization of elements is called a periodic table because it is organized in a logical and methodical way, creating patterns that are fairly simple to understand by simply looking at the table.

4) Where are elements with the highest oxide numbers located on the periodic table?

On our periodic table, the elements with the highest oxide numbers are located on the far right and far left of the table (the right side being for the most positively charged ions, and the left side being for the most negatively charged ions).

5) Where are elements with the highest boiling points located on the periodic table?

On our periodic table, the elements with the highest boiling points are located toward the right side of the table. We noticed that the more positive charges the ion had, the higher the boiling point for the element was.

6) Explain any trends you noted in your answers to Question 4 and 5.

The elements with the highest oxide numbers tended to have the highest boiling points.

7) Predict which element should have the lowest boiling point: selenium(Se), bromine(Br), or krypton(Kr). Use evidence from your graphs to explain how you decided.

Bromine should have the lowest boiling point. Out of the three elements, this element is closest to the noble gas (which does not gain any electrons to become an ion), krypton. Bromine has a positive one charge when it is an ion, and selenium has a positive two charge when it is an ion. By analyzing our graph, we noticed that generally, the higher the positive charge, the higher the boiling point of the element; therefore, bromine should have the lowest boiling.

8) Using your graphs, predict the pattern in boiling points and oxide numbers for the next 5 to 8 elements, starting with gallium.

Using our graphs, we believe the higher the oxide numbers, the higher the boiling points will be.