Final answer:
Calcium (Ca) has the stronger Coulombic attraction because it has more protons than Potassium (K), leading to a stronger pull on its electrons and necessitating more energy to remove an electron.
Step-by-step explanation:
The element with the stronger Coulombic attraction is Calcium (Ca). This is because Calcium has more protons in its nucleus compared to Potassium (K), which means that it has a more positive nucleus that can exert a stronger attraction on the surrounding electrons. Since Calcium has a +2 charge when it loses two electrons from its valence shell, it draws the remaining electrons closer compared to Potassium that only loses one electron and therefore only has a +1 charge. The removal of the 4s electron in Calcium requires more energy than the removal of the same electron in Potassium, a testament to the stronger nuclear attraction in Calcium.
So, the correct answer would be C) Calcium, more protons, because the number of protons significantly influences the Coulombic attraction within an atom. More protons mean a higher positive charge in the nucleus, which in turn increases the electrostatic force exerted on the electrons. Therefore, Calcium, having more protons, exhibits stronger Coulombic attraction.