Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
The first ionisation enthalpies of lithium, sodium and potassium are , and kJ/mol. A computed column divides by to give electron volts for one atom, rounded to two places. What values does it hold for lithium and for potassium?
A pandas DataFrame holds one element in each row. df[condition] keeps the rows where the condition is true; join conditions with &, each in brackets. sort_values("col", ascending=False) sorts from largest to smallest. set_index("symbol").loc[row, col] looks up one value. A computed column is one line, such as df["ie_eV"] = df["ie"] / 96.49.
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Lithium. eV.
Step 2. Potassium. eV.
Step 3. Check the trend. Down the group the value falls, as the outer electron is farther out.
Answer: lithium eV, potassium eV.
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