The correct formula for the Lewis dot structure you described, with fluorine atoms having three lone pairs and bonding with a beryllium atom, is: d. BeF2
The Lewis dot structure for BeF2 involves beryllium (Be) at the center, surrounded by two fluorine (F) atoms, each contributing three lone pairs. Beryllium, with two valence electrons, forms two bonds with fluorine, as each fluorine shares a single electron pair with beryllium. This results in a linear molecular geometry for BeF2. The three lone pairs on each fluorine and the two shared pairs contribute to the octet of beryllium, fulfilling the octet rule for stability.
The correct formula for this structure is BeF2, reflecting the stoichiometry of the compound. The Lewis dot structure illustrates the electron arrangement, showcasing the shared pairs and lone pairs around each atom. The absence of lone pairs on beryllium and the linear shape of the molecule comply with the VSEPR (Valence Shell Electron Pair Repulsion) theory, which predicts molecular geometry based on minimizing electron pair repulsion for increased stability.