Final answer:
Unbonded atoms within a molecule like to be distant from one another, known as (b) Distant, to minimize electrostatic repulsion based on VSEPR theory. This concept is illustrated in the linear geometry of BeH₂ and the optimal internuclear distance in H₂, defining the bond length.
Step-by-step explanation:
Unbonded atoms within a molecule like to be as far as possible from each other to minimize repulsion. Therefore, the correct answer to the question is (b) Distant. When considering the arrangement of electron pairs in a molecule, whether they are bonding pairs or lone pairs, they assume positions that maximize their distance from one another due to electrostatic repulsion. This principle is fundamental to the VSEPR theory, which helps predict the geometry of molecules based on the repulsion between electron pairs surrounding a central atom.
For example, in the linear molecule BeH₂, the two bonding pairs arrange themselves on directly opposite sides of the central beryllium atom. This configuration reflects the repulsion between bonding pairs, which dictates their position as far apart as possible, resulting in the linear geometry of the molecule. Similarly, in the case of hydrogen molecules (H₂), a stable bond forms at a specific optimal internuclear distance termed as the bond length, balancing the attractive and repulsive forces optimally.