The Lewis diagram for SeOBr2 is: The electron-pair geometry around the Se atom in SeOBr2 is fill in the blank 4. There are lone pair(s) around the central atom, so the geometry of SeOBr2 is fill in the blank 6.
The Correct Answer and Explanation is:
The electron-pair geometry around the Se atom in SeOBr2 is tetrahedral. There are one lone pair around the central atom, so the geometry of SeOBr2 is trigonal pyramidal.
Explanation:
1. Lewis Structure:
The Lewis structure of SeOBr2 involves a selenium (Se) atom as the central atom, surrounded by two bromine (Br) atoms and one oxygen (O) atom. Selenium has six valence electrons, oxygen has six, and each bromine atom has seven. So, you would need to place the electrons around the atoms in a way that satisfies the octet rule, while considering selenium’s ability to have expanded valence shells.
2. Electron-Pair Geometry:
To determine the electron-pair geometry, we need to count all the electron pairs around the central atom, including bonding and lone pairs. In SeOBr2:
- There are three bonding pairs of electrons (one for each O and Br).
- There is one lone pair of electrons on the selenium atom.
This gives a total of four electron pairs around selenium. According to the VSEPR (Valence Shell Electron Pair Repulsion) theory, four electron pairs around a central atom lead to a tetrahedral electron-pair geometry.
3. Molecular Geometry:
To find the molecular geometry, we only consider the positions of the atoms, not the lone pairs. Since there is one lone pair, it will push the bonded atoms into a less symmetrical arrangement, causing the molecular geometry to be trigonal pyramidal. This shape is similar to the tetrahedral geometry but with a “pyramid” shape due to the lone pair repulsion.
The bond angles in a trigonal pyramidal structure are typically less than 109.5°, which is the ideal angle for a perfect tetrahedral arrangement, due to the lone pair-bonding pair repulsions.
