What Is The Molecular Geometry Of BeH2 As Predicted By The VSEPR Model?
The Correct Answer and Explanation is:
The molecular geometry of BeH₂ (beryllium hydride) as predicted by the VSEPR (Valence Shell Electron Pair Repulsion) model is linear.
Explanation:
- Electron Pair Configuration:
- The central atom in BeH₂ is beryllium (Be), which has an electron configuration of 1s² 2s². In BeH₂, beryllium forms two bonds with hydrogen atoms.
- Since Be only has two valence electrons, it forms two covalent bonds with the two hydrogen atoms, resulting in two bonding pairs of electrons around beryllium.
- Beryllium does not have any lone pairs of electrons on it because it does not require more than two electrons in its valence shell to complete its bonding. Therefore, there are no lone pairs on the central atom.
- VSEPR Theory:
- According to VSEPR theory, the electron pairs around the central atom will arrange themselves as far apart as possible to minimize repulsion.
- With only two bonding pairs and no lone pairs on the central atom, the most stable arrangement is for the two bonding pairs to be positioned 180° apart, which is the characteristic geometry of a linear molecule.
- Bond Angles:
- In BeH₂, the bond angle between the two hydrogen atoms is 180°, characteristic of a linear molecular geometry.
- Hybridization:
- The central beryllium atom in BeH₂ undergoes sp hybridization. This is because there are two regions of electron density (the two bonding pairs), and the hybrid orbitals align in a linear arrangement.
- Molecular Shape:
- The molecular shape is linear, and the molecular geometry is consistent with the electron pair geometry, which is also linear.
Thus, the molecular geometry of BeH₂ is linear, with a bond angle of 180° between the hydrogen atoms.
