The complete photoelectron spectra of neutral atoms of two unknown elements, X and Y, are shown in the figure. Which of the following can be inferred from the data?   The figure presents two photoelectron spectra of neutral atoms of two unknown elements. The figure on the left is titled Element X. The figure on the right is titled Element Y. The axes of both graphs are labeled the same. The X axis is titled Binding Energy (measured in MJ per mol). The Y axis is titled Relative Number of Electrons. At the point where X and Y meet, the number 12 is shown. This begins a series of tick marks and labels on the X axis. Each tick mark is evenly spaced and labeled with a number that counts down from 12 to 0. The Element X shows begins on the Y axis with a horizontal line that is slightly above and parallel to the X axis. This graph line runs perfectly straight to the right until the space between 6 and 5 on the X axis. At this point, the graph line juts upwards and peeks quickly near the top of the graph. This graph line declines just as rapidly and settles at its original baseline before the 5. One more much smaller peak occurs between the 1 and the zero. The Element Y graph shows a horizonal line parallel to the X axis. This graph line very quickly increases in intensity to its peak and then decreases between the 12 and the 11. The graph line then resumes it original baseline trajectory for quite some time until its final spike at the 1 dash mark on the X axis. This spike is of equal intensity as the first.

The diagram shows molecules of Br2 and I2 drawn to the same scale. Which of the following is the best explanation for the difference in the boiling points of liquid Br2 and I2, which are 59°C and 184°C, respectively?  

Which of the following correctly compares periodic properties of two elements and provides an accurate explanation for that difference?

A student has samples of two pure compounds, XClO3 and ZClO3, which contain unknown alkali metals X and Z. The student measures the mass of each sample and then strongly heats the samples to drive off all the oxygen, leaving solid residues of XCl and ZCl. The student measures the mass of the solid residue from each sample. Which of the following questions can be answered from the results of the experiment?

Of the following electron configurations of neutral atoms, which represents an atom in an excited state?

Select the answer that best fits the statement: Is isomeric with CH3CH2CHO.

Which of the following best helps to explain why Na(s) is more reactive with water than Mg(s) is?

Which of the following correctly indicates whether the solid represented by the particulate model shown in the figure conducts electricity and explains why or why not?   The figure presents a particle diagram of a solid consisting of shaded circles, which represent negative ions, and smaller unshaded circles, which represent positive ions. The circles are organized in 5 rows and 5 columns, with negative ions and positive ions alternating. Ions that are adjacent are touching. The diagram shows a third dimension in the arrangement of ions. Another layer of negative ions is partly obscured by the positive ions.

What is the empirical formula of an oxide of chromium that is 48 percent oxygen by mass?

To determine the percentage of water in a hydrated salt, a student heated a 1.2346g sample of the salt for 30 minutes; when cooled to room temperature, the sample weighed 1.1857g. After the sample was heated for an additional 10 minutes and again cooled to room temperature, the sample weighed 1.1632g. Which of the following should the student do next?