We can draw an analogy between the attraction of an electron to a nucleus and seeing a lightbulb -in essence, the more \(n u=\) clear charge the electron "sees," the greater the attraction. (a) Within this analogy, discuss how the screening by core electrons is analogous to putting a frosted-glass lampshade between the lightbulb and your eyes, as shown in the illustration. (b) Explain how we could mimic moving to the right in a row of the periodic table by changing the wattage of the lightbulb. (c) How would you change the wattage of the bulb and/or the frosted glass to mimic the effect of moving down a column of the periodic table? [Section 7.2]

The shielding effect occurs when core electrons shield outer electrons from the full positive charge of the nucleus. This causes the effective nuclear charge experienced by the outer electrons to be less than the actual nuclear charge. In the analogy, the lightbulb represents the nucleus, and the brightness of the light represents the nuclear charge. The frosted glass lampshade corresponds to the core electrons, as it shields the light and reduces its intensity (like how core electrons reduce the effective nuclear charge experienced by outer electrons). In this scenario, your eyes are like outer electrons, and their attraction to the nucleus is represented by their ability to see the light.

Moving to the right in a row of the periodic table means increasing the atomic number and the nuclear charge. Therefore, in our analogy, we would increase the wattage of the lightbulb to represent a higher nuclear charge as we move to the right in the periodic table. Increasing the wattage of the lightbulb makes it brighter, hence corresponding to an increase in nuclear charge and greater attraction between the electron and the nucleus. Keep in mind, the shielding effect remains consistent across a row of the periodic table.

When moving down a column of the periodic table, there is an increase in the number of energy levels and core electrons, which leads to a greater shielding effect. In the analogy, to represent this increased shielding effect when moving down a column, we can make the frosted glass on the lampshade thicker, which will cause more of the light to be blocked. By increasing the thickness of the frosted glass, fewer light rays reach your eyes, analogous to the increased shielding effect that reduces the effective nuclear charge experienced by outer electrons. Additionally, the atomic size increases as we move down the periodic table, implying that the distance between the nucleus and the outer electron increases. In our analogy, we could represent this by placing the lampshade further away from your eyes, which will also cause you to perceive a less intense light, corresponding to a reduced effective nuclear charge.