Task: Question Generation
Input (English): Background Paragraph: However, when going across a period from left to right, the atomic radius actually tends to decrease. Why is this so? Each successive electron is going into the same principal energy level as the previous one, so the total amount of occupied space does not really go up significantly. Additionally, because protons are also added to the nucleus as you go across the row, the pull of the positively charged nucleus on the negatively charged electrons increases. This tighter pull leads to a slight decrease in atomic radius. As a result, the atomic radii of the elements exhibit a periodic trend, gradually tends to downward, but with a sharp spike up whenever electrons are added to a new principal energy level ( Figure below ). 
Story: There are two elements, Zaxon and Barton. Zaxon is an element that is further left on the period, and Barton is on the right of the period.
Output (English): Which element has a tighter pull between the nucleus and the electron?