Final answer:
Bromine (Br) can form a molecular structure that exceeds the octet rule by utilizing d orbitals to form hypervalent molecules with expanded octets.
Step-by-step explanation:
Among the choices given, the element that is able to form a molecular structure that exceeds the octet rule is bromine (Br). Bromine belongs to the third period of the periodic table, which means it has access to d orbitals that can participate in bonding, allowing it to form expanded octets. This is unlike elements of the second period, such as carbon (C) and neon (Ne), which are limited to eight electrons in their valence shell because they lack d orbitals. Boron (B) is known to sometimes form electron-deficient compounds rather than expanded octets. Elements with an expanded octet can be involved in the formation of hypervalent molecules, where they share more than four pairs of electrons with other atoms.
Examples of hypervalent molecules include phosphorous pentachloride (PCl5) where phosphorus shares five pairs of electrons for a total of ten electrons in its valence shell, and sulfur hexafluoride (SF6), where sulfur has twelve electrons in its valence shell.