The potential energy of an electron in the K-shell of the Be 3+ ion is negative due to its proximity to the nucleus. The correct answer is option C.
The statement accurately describes the negative potential energy of an electron in the K-shell of the Be3+ ion. The negative total energies of electrons arise from their bound state to the nucleus, indicating the energy required to remove them completely. As an electron moves away from the nucleus, its potential energy approaches zero. The K-shell, being the innermost electron shell, is closer to the nucleus than higher-energy shells, resulting in a more negative potential energy.
In the case of the Be3+ ion, which carries a +3 charge, it has three electrons fewer than a neutral beryllium atom. The reduction in electrons intensifies the attractive force from the nucleus on the remaining electrons, particularly the one in the K-shell. This increased attraction leads to a more negative potential energy for the electron in the K-shell of the Be3+ ion, highlighting the impact of charge alterations on electron behavior within an atom.
Therefore, option C is correct.