1. Determine the total number of valence electrons:
Se: 6 valence electrons
2 F: 2 x 7 valence electrons = 14 valence electrons
Total valence electrons = 6 + 14 = 20 valence electrons
2. Connect the atoms with single bonds:
Se is the central atom, and it forms two single bonds with two F atoms.
3. Distribute the remaining valence electrons as lone pairs:
Each F atom has three lone pairs of electrons.
Se has two lone pairs of electrons.
4. Check the octet rule:
Each atom except Se has a complete octet of electrons. Se has 10 electrons in its valence shell, considering the lone pairs. According to the expanded octet rule for elements in the third period and beyond, this is acceptable.
Therefore, the Lewis structure for SeF₂ has a central Se atom bonded to two F atoms with two lone pairs on Se and three lone pairs on each F atom.
